Upcoming Presentations

Monday, November 27, 2017

AST Colloquium: Erik Shirokoff

Erik Shirokoff University of Chicago
1275 Carlson Building
AST Colloquium

AST Colloquium: Erik Shirokoff

Erik Shirokoff University of Chicago
Monday, November 27, 2017


Monday, December 11, 2017

AST Colloquium: Chris Belczynski

Chris Belczynski University of Warsaw
1275 Carlson Building
AST Colloquium

AST Colloquium: Chris Belczynski

Chris Belczynski University of Warsaw
Monday, December 11, 2017


Friday, January 12, 2018 to Sunday, January 14, 2018

Conference for Undergraduate Women in Physics (CUWiP)

Conference

Conference for Undergraduate Women in Physics (CUWiP)

Friday, January 12, 2018

APS Conference for Undergraduate Women in Physics (CUWiP) 2018 @ RIT 

The APS Conferences for Undergraduate Women in Physics (CUWiP) are three day regional conferences for undergraduate physics majors. During January 12-14 2018, the Rochester Institute of Technology (RIT) School of Physics and Astronomy will be hosting CUWiP for students in Maine, Massachusetts (West of I-91), New Hampshire, New York (North of Poughkeepsie), Pennsylvania (Central Harrisonburg), and Vermont. RIT is located in the Eastern Standard Time zone (EST).

The goal of CUWiP is to help undergraduate women continue in physics by providing them with the opportunity to experience a professional conference, information about graduate school and professions in physics, and access to other women in physics of all ages with whom they can share experiences, advice, and ideas.

Our program will include research talks by faculty, panel discussions about graduate school, careers in physics, and inclusivity, presentations and discussions about women in physics, laboratory tours, student research talks, a student poster session, various interactive workshops and discussions, and several meals during which presenters and students interact with each other.

Full Event Schedule


Past Speakers

Wednesday, November 15, 2017

Colloidal quantum dots for light emission: phosphors, LEDs, lasing, and beyond

Oleksandr Voznyy University of Toronoto

Physics Colloquium

Colloidal quantum dots for light emission: phosphors, LEDs, lasing, and beyond

Oleksandr Voznyy University of Toronoto
Wednesday, November 15, 2017

Solution-processed nanomaterials offer low-cost alternatives to traditional bulk semiconductors. In this talk I will discuss what advantages quantum dots offer in optoelectronic applications, in particular LEDs and lasers, as well as perspectives and challenges in further improving their properties.

Recently, we have demonstrated the first implementation of a CW laser based on colloidal quantum dot thin films, after more than a decade since the first optical gain was reported in these materials. I will discuss how the understanding of electronic structure of quantum dots and its relation to optical gain motivated new chemical synthetic methods that allowed to bridge the gap between fs, ms and CW lasing. I will also talk about the next steps to building a robust QD-LED to allow for electrically injected QD laser.


Wednesday, November 8, 2017

Willy Wonka's Glass Factory: Why Chocolate is a Glass

Roger Loucks Alfred University

Physics Colloquium

Willy Wonka's Glass Factory: Why Chocolate is a Glass

Roger Loucks Alfred University
Wednesday, November 8, 2017

Contrary to popular belief, the windows in an old farm house are not thicker at the bottom because the glass has slowly flowed there over time. Glasses are not a supercooled liquid. Glasses are actually an example of a nonequilibrium system. In this talk, I will go over some of the basic properties that one encounters in glassy systems and then discuss one technique for handling nonequilibrium systems.


Wednesday, November 1, 2017

The Surface Science of Graphene Growth

Zachary Robinson SUNY Brockport

Physics Colloquium

The Surface Science of Graphene Growth

Zachary Robinson SUNY Brockport
Wednesday, November 1, 2017

Graphene, which is an atomically thin layer of graphite, was first isolated in 2004 by a research group at the University of Manchester. The discovery initiated a massive research effort into 2-dimensional materials, which have the potential to enable significant improvements in fields like high speed electronics, flexible electronics, transparent conductors, biological sensors, and others. Key to enabling future technology is understanding the physical properties and growth processes of the 2-dimensional materials. Graphene, for instance, can be grown by a variety of different techniques. Sublimation of Si from SiC and chemical vapor deposition on Cu are two such growth techniques, both of which are promising due to their ability to be scaled up to a manufacturing environment. In this talk, I will introduce some of the techniques used by surface scientists as they apply to my research studying the physical properties of the 2-dimensional material graphene.


Wednesday, October 11, 2017

From RIT Physics to the Navy: Alternative Career Paths for Physics Majors

Tighe Bailey RIT SoPA Alumnus, Navy Officer

Physics Colloquium

From RIT Physics to the Navy: Alternative Career Paths for Physics Majors

Tighe Bailey RIT SoPA Alumnus, Navy Officer
Wednesday, October 11, 2017

Ever wondered what other career opportunities are available for physics majors?  In addition to graduate school, and working in the private sector, there exist many other job opportunities for physics graduates, among them is the United States Navy.  The Navy Nuclear Propulsion Program looks for students in STEM fields to become officers in the United States Navy, working as engineers, instructors, or as officers serving aboard nuclear carriers or submarines.  In addition, the Navy will pay you to go to school!  Come learn about this unique and interesting opportunity from a former RIT student who has just completed the process.


Wednesday, September 27, 2017

Materials by Design: Accelerating Discovery and Innovation Through Computational Simulations


Physics Colloquium

Materials by Design: Accelerating Discovery and Innovation Through Computational Simulations

Wednesday, September 27, 2017

The need to discover and design materials with precise functionalities is key to modern technology. The functionality requirement in new materials make atomic and nanoscale design a necessity. However, at the nanoscale, synthesis of every new material via a trial and error approach is not only arduous, but also expensive. Recent advancements in theoretical methods along with ever-increasing computational resources have altered the interplay between computation and experiment. In this context, I will elucidate the concept of Materials by Design. Complex oxides are indispensable materials in renewable energy technologies such as fuel cells, batteries, energy storage, etc. I will elaborate on our use of computational tools based on density functional theory, molecular dynamics, and kinetic Monte Carlo methods to identify the underlying mechanisms that govern the properties of nanostructured complex oxides. Fundamental understanding of these mechanisms assists in designing nanomaterials with tailored properties. Potential research opportunities for students interested in utilizing computational physics and materials science for next-generation technology development will be discussed.


Wednesday, September 6, 2017

Physics Colloquium

Kingston Chen, Quinton LoRe & Daniel Gysbers RIT Physics Majors

Physics Colloquium

Physics Colloquium

Kingston Chen, Quinton LoRe & Daniel Gysbers RIT Physics Majors
Wednesday, September 6, 2017

Kingston Chen (Capstone I Talk)
Title: The Roles of Math Skills and Tools in Scientific Academia and Industry
Quinton LoRe (Capstone I Talk)
Title: Measurement of Alpha Crystallin During Aggregation by Light Scattering
Daniel Gysbers (Summer REU)
Title: Jamming of 2-D Sheared Granular Particles
Abstract: Granular materials are composed of many macroscopic solid particles and display solid and fluid-like characteristics.  Granular particle flow is important in the agriculture, soil, and pharmaceutical industries.  One area of interest is particle behavior under shear, when forces are applied parallel to the surface causing particles to flow over each other.  Our experiments study how circular particles behave during these shear periods with different confining pressures and pile heights.  We measure the effects of 2-D shear over long periods by filming particles in an annulus while inducing shear from the top.  We examine the velocities, bulk motion, and mean squared displacement of the particles to characterize the behavior of each system.  As predicted by theory, jamming occurs more frequently at larger confining pressures or smaller pile heights.

Wednesday, May 3, 2017

Rethinking Introductory Physics Lab Courses

Natasha Grace Holmes Cornell University

Physics Colloquium

Rethinking Introductory Physics Lab Courses

Natasha Grace Holmes Cornell University
Wednesday, May 3, 2017

In physics education research, we are taking a scientific approach to understanding and improving how we teach physics. This starts with figuring out what it is we are trying to teach (what are our goals?), and then how we can accurately measure it. The goals of lab courses have been highly debated for decades with not much research to back up any position. In this talk, I will describe new research into the goals of lab courses, how we are measuring student progress towards those goals, and the efficacy of different approaches for achieving them. I will draw comparisons to student experiences in undergraduate research, question the role of authenticity in developing an understanding of science, and discuss finding the balance between structure and autonomy.


Friday, April 28, 2017

Electronic Engines - The Principles and Practice of Solar Power Conversion

N.J.Ekins-Daukes Imperial College London.

Physics Colloquium

Electronic Engines - The Principles and Practice of Solar Power Conversion

N.J.Ekins-Daukes Imperial College London.
Friday, April 28, 2017

Civilizations throughout history have sought to harness the power of the sun, a process that nature established ~3400 million years ago trough the evolution of photosynthesis. A consequence of the semiconductor technology revolution has been our ability to manufacture affordable solar cells that convert sunlight into electricity at an efficiency of up to 20%. However, the thermodynamic limit for solar power conversion sits at 87%, suggesting there is considerable scope for improvement. Using a multi-junction architecture, photovoltaic solar cell efficiencies in excess of 40% have been demonstrated and it looks likely that a 50% efficient solar cell will be achieved within the next decade.  In the longer term it may be possible to develop materials that can support sequential optical transitions leading to the so called intermediate band solar cell or extract power from a hot electron distribution. 


Wednesday, April 19, 2017

Mechanical Quantum Systems

Matthew LaHaye Syracuse University

Physics Colloquium

Mechanical Quantum Systems

Matthew LaHaye Syracuse University
Wednesday, April 19, 2017

The field of mechanical quantum systems has made important strides in the past 10 years developing the technology to elicit and study quantum properties of motion with systems that are normally well described as behaving classically.   Such systems have promise as new components for burgeoning applications in quantum information and quantum-assisted sensing, and they offer the potential for explorations of fundamental topics in quantum mechanics like the quantum-to-classical divide.  In my talk, I will first give an overview of this growing field. Then I will highlight ongoing work in my group to develop a particular type of mechanical quantum system - a quantum electromechanical system (QEMS) - that is composed of integrated superconducting circuity and nanomechanical elements.  It is expected that such QEMS should enable the production and measurement of a variety of non-classical states of nanostructures, making these systems a potentially versatile new element for quantum processing architectures and for pursuing fundamental studies.


Wednesday, April 12, 2017

Optical beams with spatially variable polarization

Enrique Galvez Colgate University

Physics Colloquium

Optical beams with spatially variable polarization

Enrique Galvez Colgate University
Wednesday, April 12, 2017

When we think of the polarization of optical beams, the oscillation of the field vectors, we usually imagine every point in the beam having the same polarization. In our work we prepare and study optical beams where the polarization varies from point to point. They can be prepared via superpositions (interference) of two beams with orthogonal polarization and distinct spatial mode, with at least one mode carrying a phase singularity or vortex. We have observed the polarization of the light contorting in many ways within a beam, including in 3-dimensions, twisting and forming Mobius strips around the singularity. 


Wednesday, March 29, 2017

iOLabs and smartphones: New technologies for doing labs inside and outside of class


Physics Colloquium

iOLabs and smartphones: New technologies for doing labs inside and outside of class

Wednesday, March 29, 2017

The ubiquity of smartphones that are chock-full of sensors has inspired new educational technologies for labs, such as the iOLab Wireless Lab System, the Pocket Lab, and physics-focused smartphone apps (e.g., Vieyra Software Physics Toolbox Apps, https://www.vieyrasoftware.net/). These tools provide students with more autonomy collecting their own data and designing their own experiments. During the first half of the talk, I will overview my experiences using the iOLab in Fall 2016 in University Physics 1. I will describe modified UP1 labs, demos, and "real world" outside-of-class labs that utilize the iOLab, and reflect on the pros and cons of the iOLab. The second half will be an opportunity to try out the iOLab yourself! All you need to do is (1) bring your own laptop and (2) install the free iOLab application software from http://www.iolab.science/ . I'll bring about 40 iOLabs so there should be enough for everyone. The class set of iOLabs was funded by an RIT Provost's Learning Innovations Grant.
The iOLab was developed by physicist Mats Selen and the physics education research group at the University of Illinois to improve large enrollment introductory physics lab courses. The iOLab is a bundle of physics sensors (accelerometer, wheel, gyroscope, magnetic field, voltage, etc.) that interfaces wirelessly with a laptop via a free software interface.


Wednesday, March 22, 2017

Ultrafast Lasers for Photonics/Optics Fabrication and Optical Differentiation Wavefront Sensing for Astronomy and Freeform Metrology


Physics Colloquium

Ultrafast Lasers for Photonics/Optics Fabrication and Optical Differentiation Wavefront Sensing for Astronomy and Freeform Metrology

Wednesday, March 22, 2017

The research on next-generation, laser-based manufacturing technologies is highly interdisciplinary, intersecting physics, novel ultrafast laser technology, metrology, precision controls, materials, and the associated laser-material interaction processes.  The first part of the talk presents novel systems and physical mechanisms, processes using ultrafast lasers for the fabrication of photonic devices and micro- optics. The second part of the talk presents a new optical differentiation wavefront sensing technique based on measurements of wavefront slopes obtained by far-field spatial modulation with a binary pixelated filter inducing a linear amplitude transmission. This sensor is expected to offer phase measurement with higher spatial resolution, higher dynamic range and higher signal-to-noise ratio for freeform metrology lasers, vison, and astronomy applications. 


Wednesday, March 8, 2017

How I Became an Expert

Wojtek Skulski University of Rochester

Physics Colloquium

How I Became an Expert

Wojtek Skulski University of Rochester
Wednesday, March 8, 2017

When I was a kid, I loved building my own radios and destroying radios of my grandparents. I wanted to keep tinkering through the rest of my life. A physics professor told me that I should become a physicist, because physicists are tinkering more than anyone else. So I became a research physicist. About fifteen years ago I started designing electronic instruments, hoping that my kid's experience will somehow be useful in my professional life. After a while I became an expert in developing research electronics. I started a small high-tech company specialized in such instruments with many potential research applications. I will describe a particular example, where our instruments are helping uncover the nature of Dark Matter, which is holding the galaxies together. Our instruments are also used on campuses by physics faculty and students. I will end the talk by describing how you can become an expert in any activity, which you consider joyful and inspiring.


Friday, March 3, 2017

Milestones toward topological quantum computing

Ryan Mishmash Caltech

Physics Colloquium

Milestones toward topological quantum computing

Ryan Mishmash Caltech
Friday, March 3, 2017

Ordinarily, exchanging two identical quantum mechanical particles results in at most a sign change of the many-body wavefunction (+1 for bosons, -1 for fermions). However, certain low-dimensional topological phases of matter host quasiparticles which exhibit *non-Abelian* statistics: exchanging two such particles gives rise to a nontrivial unitary (matrix) rotation. Such particles — termed non-Abelian anyons — form the building blocks of a type of quantum computer which is fundamentally immune to noise at the hardware level: the topological quantum computer. In this talk, I will discuss our recent theoretical work which aims to bring the topological quantum computer closer to experimental reality by proposing a series of relatively short-term “milestone” experiments on 1D quantum wires believed to harbor *Majorana zero modes*, exotic quasiparticles which give rise to non-Abelian statistics (as well as obey the famous Majorana commutation relations). I will conclude by discussing other past, present, and future research on various problems involving exotic many-body phenomena pertinent to present day experiments on quantum condensed matter systems.


Friday, February 24, 2017

Computational materials design of next-generation nanostructured ceramic oxides

Pratik P. Dholabhai University of Colorado, Boulder

Physics Colloquium

Computational materials design of next-generation nanostructured ceramic oxides

Pratik P. Dholabhai University of Colorado, Boulder
Friday, February 24, 2017

Recent advancements in theoretical methods along with ever-increasing computational resources have altered the interplay between computation and experiment. Computational materials design offers the possibility of predicting fundamental physical and chemical attributes of existing and new materials, and thereby facilitating design of advanced materials with tunable properties before actual synthesis in a laboratory. Nanostructured complex ceramic oxides are pervasive in diverse technologies and have wide-ranging applications. I will elaborate on our recent work that entails investigation of fundamental structure-property relationships at heterointerfaces, grain boundaries, surfaces, and solids of ceramic oxides. The complementary nature of different atomistic simulation methods such as first-principles density functional theory, molecular dynamics, and kinetic Monte Carlo will be discussed. I will further demonstrate how these different simulation methods assist in elucidating the underlying mechanisms that control the properties of ceramic oxides, and lead to nanoscale design of ceramic oxides for renewable energy applications. I will briefly address how our theory-experiment collaboration has served as an effective strategy to accelerate materials discovery and design. Finally, I will give an outlook regarding the promise of computational materials design and offer a glimpse of my future research direction.


Wednesday, February 22, 2017

First-principles Simulation of Electron Localization in Real Materials

Chinedu Ekuma Naval Research Laboratory

Physics Colloquium

First-principles Simulation of Electron Localization in Real Materials

Chinedu Ekuma Naval Research Laboratory
Wednesday, February 22, 2017

There is a long history of theoretical research into electron localization. The majority of this work focuses on either disorder-induced localization or localization caused by electron interactions. These limiting cases were predicted by Philip Anderson and Nevill Francis Mott and are nowadays known as Anderson and Mott localization, respectively. We also know that both disorder and electron interactions can be substantial in real materials, especially in low-dimensional materials where electronic polarization is less effective in reducing the long-range electron interactions. Alongside experiment and theory, computation has become an essential part of the development of an understanding of many properties in real pristine solids. Despite the need, first-principles-based computer simulations of electron localization in real materials that ``properly’’ characterizes electron localization have been elusive because both disorder and electron interactions break two of the fundamental assumptions in band theory, material homogeneity, and independent particles. In this talk, I will present a new computational approach overcoming these roadblocks by combining first-principles density functional theory, the Anderson-Hubbard model, and the typical medium dynamical cluster approximation within the dynamical mean-field theory. The computer simulations enabled by this method are expected to reveal new critical insight, e.g., simulations of monolayer hexagonal boron nitride predict that both disorder and electron interactions are essential for the material to undergo an insulator-to-metal transition.


Tuesday, February 7, 2017

Flowing, squeezing, clogging, and jamming of oil droplets

Eric Weeks Emory University

Physics Colloquium

Flowing, squeezing, clogging, and jamming of oil droplets

Eric Weeks Emory University
Tuesday, February 7, 2017

We use quasi-two-dimensional emulsions as experimental models to study the flow of jammed materials. Our emulsions are oil droplets in water and are compressed between two parallel glass plates so that the droplets are deformed into pancake-like disks. We use microscopy to observe these droplets as they flow. From the deformed outlines of the droplets, we can measure all of the inter-droplet forces to within 10%. In this way, we study the relationship between the local stresses in the system and the rearrangements as the sample is sheared. The simplest rearrangement involves four droplets (a ‘T1 event’) and we confirm theoretical predictions for the quadrupolar spatial pattern of the stress redistribution around the T1 events. We also study gravity-driven flow in hoppers and investigate the probability of clogging as a function of the hopper exit size. Here, experiments and simulations show that the softness of the particles is important, as soft particles form less stable arches and thus reduce the probability of clogging.


Wednesday, December 7, 2016

Symmetry in Theoretical Physics: From Newton to the Standard Model to GUTs to SUSY and Beyond


Physics Colloquium

Symmetry in Theoretical Physics: From Newton to the Standard Model to GUTs to SUSY and Beyond

Wednesday, December 7, 2016

Classical physics includes many important conservation laws which were established through experiment.  Looking back these conservation laws can be explained as the consequence of symmetry.  For the advancement of Modern Physics in the early Twentieth Century, theory, including applications of symmetry, played a vital role in the understanding of relativity, particle spin and anti-matter.  Theoretical considerations of symmetries and broken symmetry led the development of the Standard Model of Elementary Particles, and these same considerations provide tantalizing clues to what may yet be discovered.  This discussion will provide a high-level overview of these concepts without all of the mathematics and technical complications.

 


Wednesday, November 16, 2016

How might Physics Education Research facilitate the coming computational revolution?

Danny Caballero Michigan State University

Physics Colloquium

How might Physics Education Research facilitate the coming computational revolution?

Danny Caballero Michigan State University
Wednesday, November 16, 2016

Hosted by the School of Physics & Astronomy, SMERC & CASTLE

Computation has revolutionized how modern science is done. Modern scientists use computational techniques to reduce mountains of data, to simulate impossible experiments, and to develop intuition about the behavior of complex systems. Much of the research completed by modern scientists would be impossible without the use of computation. And yet, while computation is a crucial tool of practicing scientists, most modern science curricula do not reflect its importance and utility. In this talk, I will discuss the urgent need to construct such curricula in physics and present research that investigates the challenges at a variety of all scales -- from the largest (institutional structures) to the smallest (student understanding of a concept). I will discuss how the results of this research can be leveraged to facilitate the computational revolution.  This research will help us understand and develop institutional/departmental incentives, effective teaching practices, evidence-based course activities, and valid assessment tools. 


Wednesday, November 2, 2016

Cell Mechanics: How Cells Regulate Force Generation

Patrick Oakes University of Rochester

Physics Colloquium

Cell Mechanics: How Cells Regulate Force Generation

Patrick Oakes University of Rochester
Wednesday, November 2, 2016

: In the absence of mechanical interactions, cells would mostly be just round spheres, unable to engineer even the most rudimentary shape changes that are necessary in physiological processes like migration. The cell’s ability to alter its shape is built upon the capacity to coordinate processes like adhesion, polymerization and contraction events in both space and time. In particular, while we know significant amounts about the biochemical interactions that allow cells to generate forces, we have surprisingly little knowledge of how these molecular interactions are integrated to produce contractile behavior at the scale of the cell. In this talk I will discuss how we can use approaches from physics to describe the cell cytoskeleton as a material with dynamic properties that help to regulate this contractile behavior in adherent cells. 


Wednesday, October 26, 2016

A Physicist's Perspective on Closed Traumatic Brain Injury and its Mitigation

Eric Blackman University of Rochester

Physics Colloquium

A Physicist's Perspective on Closed Traumatic Brain Injury and its Mitigation

Eric Blackman University of Rochester
Wednesday, October 26, 2016

Brain injury without skull fracture, called "closed traumatic brain injury” (TBI),   is  a large public health problem that affects soldiers and civilians of all ages. Blast waves and head Impacts are sources of brain injury in military contexts while impacts are dominant in civilian contexts. 

In sports,  impact-induced TBI results from both concussive and repeated sub-concussive  head impacts, the latter only manifesting as long term brain damage with present diagnostics. I will first highlight the history of evidence  for TBI in both military and sports contexts.  I will then  discuss progress and challenges in understanding mechanisms  of how the brain is injured.  I will explain why current helmets are deficient from a  physics perspective  and  offer some simple recommendations for both improving helmets, along with  strategies  for interdisciplinary research in both helmet protection and connecting physics to physiology.  Physics training is essential for tackling some frontier aspects of this enterprise.


Friday, October 21, 2016

Raman Spectroscopy: Using Light to Speed Up Medical Diagnosis

Dustin Shipp University of Nottingham

Physics Colloquium

Raman Spectroscopy: Using Light to Speed Up Medical Diagnosis

Dustin Shipp University of Nottingham
Friday, October 21, 2016

Among women, breast cancer is the second most common type of cancer after skin cancer. The tumor is often removed through surgery. For many patients, this surgery can remove the tumor and preserve much of the surrounding tissue. However, over 20% of these patients must undergo a second surgery to remove residual cancer tissue. This high re-excision rate is largely due to the inherently slow process of evaluating the tumor margins of the removed tissue.
Raman spectroscopy may provide a solution to this problem. Raman spectroscopy is an optical method that non-invasively measures chemical concentrations. This spectral fingerprint can be used to diagnose biological tissues and cells. This talk will discuss the creation of a diagnostic model based on Raman spectroscopy. The measurement procedure can be accelerated through the use of multi-modal imaging, image processing, and multifocal spectroscopy. Spatially-offset Raman spectroscopy (SORS) could also allow future systems to probe deeper into tissues. The talk will also discuss the integration of this system into current clinical practice as well as the opportunities and challenges of collaborating with medical professionals.


Wednesday, October 19, 2016

Thinking about round cows: Introductory Physics for Life Science Students

Dawn Meredith University of New Hampshire

Physics Colloquium

Thinking about round cows: Introductory Physics for Life Science Students

Dawn Meredith University of New Hampshire
Wednesday, October 19, 2016

The introductory physics course for life science majors (IPLS) has been the focus of reform over the last 10 years.  I will talk about the challenges and successes in teaching this course, and why it should not be just an algebra-based  version of the course for engineers.  I will also talk about our focus on developing and assessing tutorials on static and moving fluids, and how we used the resources framework to inform our development and recognize productive student work.


Friday, September 30, 2016

Ab-Initio Study of Electron Localization in Low-Dimensional Materials

Chineda Ekuma Naval Research Laboratory / Future Faculty Career Exploration Program

Physics Colloquium

Ab-Initio Study of Electron Localization in Low-Dimensional Materials

Chineda Ekuma Naval Research Laboratory / Future Faculty Career Exploration Program
Friday, September 30, 2016

Correlated materials are promising for exploring the possibility of engineering new or improved materials as to meet the demands of the 21st century. Because their properties emerge from rather a complex competition between the electron degrees of freedom often on different length scales that can be tuned to improve device performance. Materials are often prone to defects and at the nanoscale, these inhomogeneities appear to be intrinsic. Besides, extrinsic doping can lead to a better understanding of the ground state properties of materials. To study disordered materials, the density functional theory using supercell approach (DFT-Sc) or the single-site coherent potential approximation (CPA) and cluster extensions are the frequently used computational methods. While the CPA and its extensions deal explicitly with algebraically, average statistical disorder distributions, the DFT-Sc can only describe ordered defect structures. Because CPA self-consistency uses arithmetically, averaged density of states (DoS), it does not adequately account for rare events that induce electron localization, e.g., in disordered materials. In this talk, I will discuss a first-principles, Typical Medium Dynamical Cluster Approximation (TMDCA@DFT) that appropriately characterizes disordered materials. The TMDCA@DFT, unlike the CPA, uses the typical DoS defined as the geometric average of the local DoS as the intrinsic order parameter for characterizing localization transitions.

Wednesday, September 21, 2016

Plasma, Fusion and PPPL: The Quest for Making a Star on Earth and info on Princeton Conference on UG Women in Physics

Arturo Dominguez Princeton Plasma Physics Laboratory

Physics Colloquium

Plasma, Fusion and PPPL: The Quest for Making a Star on Earth and info on Princeton Conference on UG Women in Physics

Arturo Dominguez Princeton Plasma Physics Laboratory
Wednesday, September 21, 2016

The challenge of developing sustainable, safe, environmentally friendly sources of energy is one of the most important scientific endeavors of the modern world.  At the Princeton Plasma Physics Laboratory, research is being conducted on various fields of plasma physics, including the primary mission of the lab, the development of fusion energy as an alternative energy source.  This presentation will discuss the physics of fusion plasmas, the challenges towards the goal of a fusion future, and the opportunities available at PPPL for research, including undergraduate internships.


Wednesday, September 7, 2016

Student Summer Research Experiences


Physics Colloquium

Student Summer Research Experiences

Wednesday, September 7, 2016

2016 Summer Research Experiences
Christian Cammarota 
Surface Structure and Composition: Gas Phase Catalyst Creation and Measurement
Kellianne Kornick 
The Population Dynamics of Mitochondria in Mammalian Cells
Roland Sanford
Noninvasive Electrocardiographic Imaging  in Localizing Atrial Arrhythmia Sources
 

Tuesday, April 19, 2016

Spintronics: Fundamentals and Applications

Alex Matos Abiague SUNY Buffalo

Physics Colloquium

Spintronics: Fundamentals and Applications

Alex Matos Abiague SUNY Buffalo
Tuesday, April 19, 2016

The need for faster, more powerful and yet more efficient devices has led to the emergence of Spintronics (or spin electronics) as an alternative to conventional electronics. Unlike conventional electronic devices, which rely on the transport of electrical charge carriers, spintronic devices use electron spins for building operational functionalities such as nonvolatile information storage, sensing, and logics. Typically, spins are manipulated by external magnetic fields, but solid state materials offer a great potential for all-electric spin manipulation by means of effective, momentum-dependent “magnetic” fields, the so-called spin-orbit fields. Those fields account for spin-orbit interactions and can be exceptionally large in some materials, which, as a consequence, exhibit exotic topological properties.
This talk will focus on the physical origin, characterization, and engineering of interfacial and synthetic spin-orbit fields and their effects on anisotropic magnetoresistive phenomena and topological quantum matter. Key implications of spin-orbit-mediated transport for a new generation of nonvolatile devices, as well as present challenges in their way to applications will also be addressed.

Thursday, April 14, 2016

Rational design of electrode materials for energy storage

Roberto Longo Pazos University of Texas, Dallas

Physics Colloquium

Rational design of electrode materials for energy storage

Roberto Longo Pazos University of Texas, Dallas
Thursday, April 14, 2016

For over 20 years, Li-ion batteries have enabled the rise of portable electronics, dominating the battery market. Current Li-ion batteries use layered oxides as cathode materials, specially LiCoO2, organic liquid electrolytes and graphite as anode. However, Co layered oxides and organic liquid electrolytes suffer from certain instability at high operational temperatures and flammability, respectively. In this colloquium, using first principles density-functional theory, I will examine the main characteristics of the most promising alternatives for electrode and solid-electrolyte materials, suggesting suitable pathways to improve their conceptual design and performance, thus serving as design principles for future discovery of electrode materials. 


Wednesday, April 13, 2016

Spontaneous parametric down conversion with a depleted pump as an analogue for black hole evaporation/particle production

Paul Alsing Air Force Research Laboratory

Physics Colloquium

Spontaneous parametric down conversion with a depleted pump as an analogue for black hole evaporation/particle production

Paul Alsing Air Force Research Laboratory
Wednesday, April 13, 2016

In this talk, I argue that black hole evaporation/particle production has a very close analogy to the laboratory process of spontaneous parametric down conversion, when the laser pump source is allowed to deplete. I will first present an overview of the essential features of the Unruh and Hawking effect and its analogy to the quantum optical process of spontaneous parametric down conversion widely used in the field of quantum information science as a source of photon-based qubits. In the previous case, the pump is considered a constant (i.e. non-depleted). I will next discuss the case when the black hole is treated as a finite `pump' source which is allowed to deplete, hence modeling the processes of black hole evaporation and Hawking radiation production. This model reproduces essential features of the Page Information curves (conjectured by D. Page, 1993) which are widely believe to describe the rate at which information escapes from the black hole as it evaporates, as the Hawking radiation deviates at late times from the pure thermal spectrum characterized by early black hole evolution times. Further details of this work can be found in (i) P.M. Alsing: Class. & Quant. Grav. 32, 075010, (2015); (arXiv:1408.4491), and (ii) P.M. Alsing & M.L. Fanto: Class. & Quant. Grav. 33, 015005 (2016), (arXiv:1507.00429).


Wednesday, April 6, 2016

First-principles theory-driven materials design and innovation in all-solid-state batteries

Yan Wang MIT

Physics Colloquium

First-principles theory-driven materials design and innovation in all-solid-state batteries

Yan Wang MIT
Wednesday, April 6, 2016

Emergent energy technologies are critically limited by materials performance and therefore highly dependent on materials innovation. The efficient design and discovery of new functional materials with desired performance represent formidable challenges to materials scientists. The ability to accurately predict key materials properties using first-principles computational methods, even before the materials synthesis and characterization, has made virtual materials design a reality. However, successful computation-based materials design often requires theoretical insights on the appropriate descriptors (genes) for the identification of candidate materials. In this seminar, I will present our recent efforts in theory-driven materials design and innovation in lithium superionic conductors and all-solid-state batteries using the computational materials genome approach. I will share our research breakthrough in theoretical identification of the gene for good ionic conductors by revealing the fundamental relationship between structural topology and ionic transport. Furthermore, an accurate and efficient first-principles computational methodology has been developed to evaluate thermodynamic stability of the solid-state electrolyte against electrodes at the battery interfaces. These findings not only provide valuable insights towards the understanding of materials behaviors in discovered ionic conductors, but also serve as design principles for new ionic conducting materials and all-solid-state batteries. Finally I will give an outlook on the potential of computational materials design for novel energy technologies.

Wednesday, March 9, 2016

Thin-film Electronics by Spatial ALD: Achieving High Performance with Low Process Complexity

Shelby F. Nelson Eastman Kodak Company

Physics Colloquium

Thin-film Electronics by Spatial ALD: Achieving High Performance with Low Process Complexity

Shelby F. Nelson Eastman Kodak Company
Wednesday, March 9, 2016

Patterning thin-film transistors for “printed electronics” applications can be challenging both for resolution and for alignment accuracy. This is particularly true for high-performance devices with submicron channel lengths, and for diverse and deformable substrates. Printing organic-based devices has additional issues such as printing dynamics, and orthogonality of solvents.  In this talk, I will describe alternative approaches to scalable thin-film electronics based on spatial atomic layer deposition (SALD) of metal oxides. Using the relatively high deposition speed of SALD, the conformality of the deposited layers, and the surface-sensitivity of the technique, we have explored both print-compatible high-performance vertical transistors, and patterned-by-printing circuitry. A reliable ZnO mobility above 10 cm2/Vs, on-off ratio above 107, and uniform threshold voltage values across the substrate give these approaches promise for large-area applications.


Wednesday, February 24, 2016

The Dawn of Gravitational Wave Astronomy

John T. Whelan RIT School of Mathematical Sciences and Center for Computational Relativity and Gravitation

Physics Colloquium

The Dawn of Gravitational Wave Astronomy

John T. Whelan RIT School of Mathematical Sciences and Center for Computational Relativity and Gravitation
Wednesday, February 24, 2016

Gravitational waves are ripples in the geometry of space and time which propagate at the speed of light, predicted by Einstein's General Theory of Relativity. Last fall, the Advanced LIGO detectors in Louisiana and Washington State began their first observing run, resulting in the recently reported first direct detection of gravitational waves, from a binary black hole inspiral, merger and ringdown. This first gravitational wave observation kicks off the field of Gravitational Wave Astronomy. I will present an overview of: 1) the science done so far with detectors such as LIGO and the Virgo and GEO600 detectors in Italy and Germany, 2) the most promising prospects for future observations with Advanced LIGO, Advanced Virgo, and planned detectors such as KAGRA (Japan) and LIGO India, and 3) the involvement of RIT scientists in the gravitational-wave enterprise.

Wednesday, December 2, 2015

The benefits of low permeability in articular cartilage

Mark Buckley University of Rochester

Physics Colloquium

The benefits of low permeability in articular cartilage

Mark Buckley University of Rochester
Wednesday, December 2, 2015

Abstract: Articular cartilage is a durable, load-bearing, poroelastic tissue that coats bones in joints and protects them from damage over several decades. Unfortunately, trauma-induced cartilage cell (chondrocyte) death can initiate a cascade of degradative alterations in the joint. In this talk, I will discuss how a key property of articular cartilage – its hydraulic permeability – mediates its ability to withstand extreme forces in two distinct ways. First, since exudation of fluid facilitates tissue compression, low permeability delays tissue deformation and allows chondrocytes to survive brief periods under extreme loads that would otherwise be fatal. Second, because permeability is low in articular cartilage and further decreased when the tissue is compressed, harmful intracellular contents that are released in areas where cell death occurs always flow towards the point of contact rather than towards healthy, uninjured cells. This protective feature could prevent the spread of cell death and contribute to the durability of articular cartilage. Finally, I will discuss a separate phenomenon related to cartilage longevity that our experiments have recently revealed: the ability of chondrocytes to adapt to recently imposed physical forces and thereby become less susceptible to subsequent mechanical injury. 


Wednesday, November 4, 2015

Unexpected ordered phases in active systems

Michael Hagan Brandeis University

Physics Colloquium

Unexpected ordered phases in active systems

Michael Hagan Brandeis University
Wednesday, November 4, 2015

Active matter describes systems whose constituent elements consume energy to generate motion or forces. Since these systems are intrinsically nonequilibrium, they can exhibit collective behaviors unlike anything possible in a traditional equilibrium material. In this talk I will describe computer simulations of two recently developed model active matter systems,  self-propelled colloidal particles and extensile active nematics, and unexpected ordered phases that arise as a consequence of activity in these systems.

When colloidal particles are asymmetrically coated with a catalyst and placed in the presence of a fuel, they undergo directed motion. An idealized model for such particles, self-propelled spheres with repulsive interactions and no aligning interactions, has become an intensely studied theoretical and computational model system. We and others have recently shown that this system undergoes a continuous phase transition analogous to that of equilibrium systems with attractive interactions. Particles in the dense phase form ‘active crystals’ with hexatic or crystalline order but efficient transport properties. I will discuss some new features of this system; then, I will show that when these particles are confined they undergo another transition, in which the particles become confined to the boundary, with a density that depends on the local curvature radius of the boundary.  A theory describing this behavior allows designing boundary shapes that lead to a wide variety of particle density distributions.

Active nematics are liquid crystals which are driven out of equilibrium by energy-dissipating active stresses.  The ordered nematic state is unstable in these materials, due to the spontaneous generation of topological defects, which undergo birth, streaming dynamics, and annihilation to yield a complex, seemingly chaotic dynamical steady-state.  In this talk, I will show that order emerges from this chaos, in the form of heretofore unknown broken-symmetry phases in which the topological defects themselves undergo orientational ordering. I will describe the appearance of these phases into realizations of an active nematic: (1) an experimental system containing extensile bundled microtubules and molecular motor proteins studied by the Dogic lab at Brandeis, and (2) a computational model of extending hard rods.  I will describe the defect-stabilized phase that manifests in each system and our current understanding of their origins.  Such phases may be a general feature of extensile active nematics.


Wednesday, October 14, 2015

Pentaquarks: Quark Model Revisited

Tomasz Skwarnicki Syracuse University

Physics Colloquium

Pentaquarks: Quark Model Revisited

Tomasz Skwarnicki Syracuse University
Wednesday, October 14, 2015

 The LHCb experiment has recently reported the observation of pentaquark candidates: bound states of four quarks and an antiquark. Such objects have been predicted for over 50 years, but until recently believed not to exist. I will describe the bumpy road which led to this recent observation, starting from the birth of the Quark Model, through its spectacular success in describing known mesons and baryons and searches for quark structures made out of more than the minimal quark content. I will describe the LHCb pentaquark measurement and conclude with implications of the recent observations of tetraquark and pentaquark candidates on our understanding of the fabric of matter made out of quarks.
 

Wednesday, September 30, 2015

Shearing While Looking at Nonlinear Soft Materials

Daniel Blair Georgetown University

Physics Colloquium

Shearing While Looking at Nonlinear Soft Materials

Daniel Blair Georgetown University
Wednesday, September 30, 2015


Wednesday, September 9, 2015

Physics Colloquium: Summer REUs

Tyler Godat, John Collini, & Luke Shadler RIT Physics Majors

Physics Colloquium

Physics Colloquium: Summer REUs

Tyler Godat, John Collini, & Luke Shadler RIT Physics Majors
Wednesday, September 9, 2015


Wednesday, April 15, 2015

Breaking The Myth of the "Non-Traditional" Physicist: The Real Story About Employment for Physics Graduates

Crystal Bailey American Physical Society (APS)

Physics Colloquium

Breaking The Myth of the "Non-Traditional" Physicist: The Real Story About Employment for Physics Graduates

Crystal Bailey American Physical Society (APS)
Wednesday, April 15, 2015


Monday, March 2, 2015

Characterizing Exoplanet Atmospheres through Our Own

Sloane Wiktorowicz University of California, Santa Cruz

Physics Colloquium

Characterizing Exoplanet Atmospheres through Our Own

Sloane Wiktorowicz University of California, Santa Cruz
Monday, March 2, 2015


Tuesday, November 14, 2017

Diffraction Grating Technology: Enabling Everything from Smartphones, to Increases in Network Bandwidth, to Earthlike Exosolar Planet Discoveries

Jason Rama Richardson Grating Lab/MKS Instruments Inc.

Photons After Dark

Diffraction Grating Technology: Enabling Everything from Smartphones, to Increases in Network Bandwidth, to Earthlike Exosolar Planet Discoveries

Jason Rama Richardson Grating Lab/MKS Instruments Inc.
Tuesday, November 14, 2017

Although the principles of diffraction gratings have been known for centuries, these spectrally dispersing devices have recently become an ever more critical component to clarify our understanding of the cosmos, enable microelectronic (and optoelectronic) technology, and equip a broad assortment of instrument technologies for chemistry analyses.  They are present anywhere a range of optical spectra must be either generated or detected in a precise way.  In this talk, the technology, fabrication, figures of merit, design requirements, markets, and applications of diffraction gratings will be touched upon, all with a mind for critical business and technology commercialization considerations.


Wednesday, October 18, 2017

An Introduction to Ursa Space Systems, Inc., and SAR Analytics

Mat DePasquale Ursa Space Systems

Photons After Dark

An Introduction to Ursa Space Systems, Inc., and SAR Analytics

Mat DePasquale Ursa Space Systems
Wednesday, October 18, 2017

Ursa Space Systems, Inc. is a technology startup which aggregates and analyzes satellite-based radar to build proprietary data layers resulting in unbiased, consistent, all-weather locationbased services and measurements. Ursa is bridging the gap between advanced SAR analytics and commercial customers. This is an introduction to the company that includes products, technologies, and opportunities for students in various technical disciplines.


Wednesday, September 13, 2017

Novel Materials and Nanostructures for Photovoltaic Energy Conversion


Photons After Dark

Novel Materials and Nanostructures for Photovoltaic Energy Conversion

Wednesday, September 13, 2017

The world demand for, and consumption of, energy is dramatically increasing, with an increasing demand for renewable non-fossil based sources of electricity. As well, there is an ever growing demand for increased power and sophistication in the satellite systems orbiting our planet, driven by our increasing reliance on high speed communication and data links. The conversion of light from the sun into electrical energy, using photovoltaics, is one avenue that can be explored to meet these challenges both on the earth and in space, with III-V’s being the most promising materials for very high efficiency devices.  At RIT, our team’s expertise lies in vapor phase epitaxy (VPE) of III-V photonic devices and nanostructures, bandgap engineering using epitaxial nanostructures, novel photovoltaic devices such as the intermediate band solar cell and potential routes for low cost high efficiency III-V multijunction devices.  This talk will give an overview of PV research at RIT, a discussion of the nanomaterials approach and specific results using quantum dot (QD) superlattices, Sb-based photovoltaic materials development and finally some recent results on developing low-cost substrates for III-V materials.  During the talk, we will show the effects of QD solar cell design on both absorption and open circuit voltage and discuss the nature of carrier escape and recombination paths inherent to QD solar cells.  As well, we will discuss the growth and processing of an InAlAsSb alloy for photovoltaic applications as well as GaSb solar cells grown on GaAs using the interfacial misfit (IMF) technique.  The last topic will include a cost breakdown of III-V photovoltaics and recent results using polycrystalline Ge as a template for growth of III-V solar cells.  

Wednesday, April 26, 2017

Polarized Vision for Astronomers and Other Humans

Dmitry Vorobiev RIT

Photons After Dark

Polarized Vision for Astronomers and Other Humans

Dmitry Vorobiev RIT
Wednesday, April 26, 2017

Humans have long benefitted from our ability to distinguish light of different frequency based on its color. Sadly, our eyes are not sensitive to the polarization of light. As a result, we are far less familiar with the utility of polarimetric measurement. Devices to measure polarization are relatively rare and expertise in polarimetry even more so. Polarization sensors based on micropolarizer arrays appear to be the first devices capable of bringing polarimetric capability to a wide range of applications. Based on a combination of theoretical models and lab-based measurements, I conclude that the current generation of these devices can measure fractional polarization as small as 0.5%, across the visible and near-infrared spectrum, with potential for further improvement. I will present some astronomical observations acquired with the RIT Polarization Imaging Camera and end with a discussion of applications outside of astronomy that are well-positioned to benefit from these sensors.


Wednesday, March 8, 2017

Making a go of it with licensed technology – Low Coherence Interferometry from Kodak and Shack-Hartmann from AMO-Abbott

David Compertore Lumetrics

Photons After Dark

Making a go of it with licensed technology – Low Coherence Interferometry from Kodak and Shack-Hartmann from AMO-Abbott

David Compertore Lumetrics
Wednesday, March 8, 2017

Formed in March 2003 Lumetrics grew from 3 employees to 20 originally on the strength of the LCI product and in 2012 adding the Shack-Hartmann line.  Lumetrics is a “Photonics” company serving a diverse customer base including medical, industrial, electronics, automotive, food packaging, glass, adhesives markets.  Lumetrics one main optics market is the intraocular & contact lens ophthalmic industry, an industry known for making purposefully “bad” optics.


Wednesday, February 8, 2017

Manufacturing High Precision Optics using MRF and SSI Technologies

Chris Maloney QED Technologies, Inc

Photons After Dark

Manufacturing High Precision Optics using MRF and SSI Technologies

Chris Maloney QED Technologies, Inc
Wednesday, February 8, 2017

QED Technologies was founded about 20 years ago, leveraging Magnetorheological Finishing (MRF) and Subaperture Stitching Interferometry (SSI) technologies that were developed at the University of Rochester. These two technologies for polishing and metrology provide a deterministic method for manufacturing high precision spheres, aspheres and freeform optics. In this seminar we will discuss the theory behind MRF and SSI technologies as well as how they are used in the optical manufacturing industry.


Thursday, November 17, 2016

Advances in Manufacturing and Metrology of Optical Freeform Surfaces

Ian Ferralli and Michael Rinkus RIT Alumni, Optimax

Photons After Dark

Advances in Manufacturing and Metrology of Optical Freeform Surfaces

Ian Ferralli and Michael Rinkus RIT Alumni, Optimax
Thursday, November 17, 2016

Designing optical systems using freeform optical components can provide many advantages to the optical designer such as fewer optical components and less distortion. Techniques for manufacturing these complex geometries are advancing very quickly with increasing demand. Additionally, the metrology of freeform optics has progressed enabling higher precision surfaces to be made. We will explain the ongoing research efforts at Optimax that enable us to be at the forefront of optical manufacturing capability.


Wednesday, September 14, 2016

Measuring the Largest Structures in the Universe with the Smallest Telescopes in Space


Photons After Dark

Measuring the Largest Structures in the Universe with the Smallest Telescopes in Space

Wednesday, September 14, 2016

Observational astrophysics has always been driven by the race to build telescopes with larger and larger apertures. However, telescopes with very small apertures can perform cosmological measurements as important as their larger siblings. In this talk, I will present several examples of small aperture, space-based experiments providing unique views on the large scale structure of the universe. My discussion will include The Cosmic Infrared Background Experiment (CIBER) that has successfully measured the amplitude of the near-IR background fluctuations on arcminute scales; SPHEREx, a spectrometric instrument designed to probe the inflationary history of the universe and the evolution of galaxies; and work using the Long Range Reconnaissance Imager (LORRI) on New Horizons to measure the cosmic optical background.


Thursday, April 21, 2016

Field E ect Electro-Absorption Modulator Based on Conductive Oxide

Kaifeng Shi Novel Material Photonics Group Rochester Institute of Technology

Photons After Dark

Field E ect Electro-Absorption Modulator Based on Conductive Oxide

Kaifeng Shi Novel Material Photonics Group Rochester Institute of Technology
Thursday, April 21, 2016

The lack of ultracompact, high speed, broadband electro-optical (EO) modulators impedes the wide applications of integrated photonic circuits. Novel approaches and materials need to be explored to overcome the technical barrier. In this talk, I will present an EO mod-ulator, more speci cally electro-absorption (EA) modulator, based on a novel yet inexpensive active material, conductive oxide (COx), which exhibits moderate carrier concentration for tele-com application. Light modulation is realized through the eld e ect in a metal-insulator-COx(MIC) structure. Dielectric constant epsilon-near-zero (ENZ) state is observed. Furthermore, we investigate an MICIM plasmonic EA modulator with a waveguide length of only 800 nm. The modulator can potentially operate at high speed.


Tuesday, March 15, 2016

Quantum Integrated Photonics: A source of spectrally indistinguishable photons

Michael L. Fanto Nanophotonics Group @ RIT

Photons After Dark

Quantum Integrated Photonics: A source of spectrally indistinguishable photons

Michael L. Fanto Nanophotonics Group @ RIT
Tuesday, March 15, 2016

Quantum information science relies on the property of quantum interference, where the interference quality correlates to the indistinguishability of the interacting particles. The creation of these indistinguishable particles, photons in this case, has conventionally been accomplished with nonlinear crystals and optical filters to remove spectral distinguishability, albeit sacrificing the number of photons. This research describes the use of an integrated silicon microring resonator circuit to selectively generate photon pairs at the narrow cavity transmissions, thereby producing spectrally indistinguishable photons, and then entangle the resulting photon pair.


Wednesday, February 17, 2016

Designing a spatial mode sorting interferometer

Tanya Malhotra University of Rochester

Photons After Dark

Designing a spatial mode sorting interferometer

Tanya Malhotra University of Rochester
Wednesday, February 17, 2016

The ability to decompose an optical beam/scene into a specific modal basis is desirable in a wide array of optical technologies. By generalizing the delay line in a conventional Michelson interferometer to an arbitrary unitary transformation, it becomes possible to unlock the full mode sorting ability of the interferometer. Specifically, the eigenfunctions of the generalized delay line are the basis in which beam modal analysis is possible. In the following we describe an approach to arbitrary spatial mode sorting based on two-path interferometry. Our proof-of-principle mode sorting demonstration is based on the fractional Fourier transform (fFT). When replacing the conventional temporal delay line in the interferometer with an optical implementation of the fFT, the interferometer is able to decompose an input optical beam in terms of its constituent HG modes which are the fFT eigenmodes.


Wednesday, November 18, 2015

State transfer based on classical nonseparability

Seyed Mohammad Hashemi Rafsanjani Institute of Optics @ the University of Rochester

Photons After Dark

State transfer based on classical nonseparability

Seyed Mohammad Hashemi Rafsanjani Institute of Optics @ the University of Rochester
Wednesday, November 18, 2015

We discuss recent interest in appearance of entanglement in classical physics. We demonstrate a protocol that utilizes nonseparability between different degrees of freedom of a beam of light to transfer an arbitrary and a priori unknown, state of two different OAM modes onto the polarization, in a fashion that is analogous to teleportation using quantum entanglement.


Tuesday, October 13, 2015

Exotic Effects in Optical Coherence

Omar S. Magaña-Loaiza Institute of Optics @ the University of Rochester

Photons After Dark

Exotic Effects in Optical Coherence

Omar S. Magaña-Loaiza Institute of Optics @ the University of Rochester
Tuesday, October 13, 2015

In this talk I will describe our recent contributions to the field of exotic effects in optical coherence. I will start by describing how the chaotic fluctuations of light can give rise to the formation of correlations in the orbital angular momentum (OAM) components and angular positions of pseudothermal light. The presence of these correlations is manifested through a new family of exotic interference structures in the OAM distribution of random light.  In addition, it has been recently predicted that the finite probability of a photon to follow looped paths in a three-slit interferometer produces an apparent deviation from the most conventional form of the superposition principle. However, the probability of observing these exotic paths is very small and thus extremely hard to be measured. I will discuss how we have increased the probability of photons to follow such looped trajectories and measured its contributions to the formation of interference fringes. 


Wednesday, September 16, 2015

Photons After Dark: Robin Sharma

Robin Sharma Institute of Optics @ the University of Rochester

Photons After Dark

Photons After Dark: Robin Sharma

Robin Sharma Institute of Optics @ the University of Rochester
Wednesday, September 16, 2015

 

 


Wednesday, April 15, 2015

Twisting starlight to directly image exoplanets

Garreth Ruane RIT, Center for Imaging Science

Photons After Dark

Twisting starlight to directly image exoplanets

Garreth Ruane RIT, Center for Imaging Science
Wednesday, April 15, 2015


Wednesday, March 18, 2015

A physicist in the woods: closing the fire energy budget


Photons After Dark

A physicist in the woods: closing the fire energy budget

Wednesday, March 18, 2015


Wednesday, November 19, 2014

Measuring Photons with a "Light" touch

Mohammad Mirhosseini Institute of Optics @ the University of Rochester

Photons After Dark

Measuring Photons with a "Light" touch

Mohammad Mirhosseini Institute of Optics @ the University of Rochester
Wednesday, November 19, 2014


Monday, November 13, 2017

Black Hole Feedback in Action? Understanding the role of AGN in transitioning Galaxies

Lauranne Lanz Dartmouth College

AST Colloquium

Black Hole Feedback in Action? Understanding the role of AGN in transitioning Galaxies

Lauranne Lanz Dartmouth College
Monday, November 13, 2017

In past several decades, we have made great progress in developing a consistent paradigm for the formation and evolution of galaxies, seeking to answer the basic question of where galaxies like our Milky Way come from and where we are headed on cosmic timescales. However, many details of this picture remain unclear. One particularly interesting question regards the role that active supermassive black holes play in the transition from a gas-rich, actively star forming state to gas-poor quiescence. I will describe a recently discovered type of galaxies at an earlier stage of transition that the classical post-starburst galaxies, and present new X-ray observations of these galaxies, which provide a crucial window into the role of AGN in the early phases of transformation. 


Monday, October 30, 2017

Enabling Infrared Surveys of Galaxies with Innovative Imaging Spectrographs

Suresh Sivanandam University of Toronto

AST Colloquium

Enabling Infrared Surveys of Galaxies with Innovative Imaging Spectrographs

Suresh Sivanandam University of Toronto
Monday, October 30, 2017

Optical integral field (imaging) spectroscopic surveys of large numbers of galaxies are now becoming the norm. These surveys allow detailed studies of individual galaxies, such as their kinematics and stellar ages/metallicities. With a sufficiently large sample, these types of observations are the best tools for understanding the formation and evolution of galaxies. However, similar surveys in the infrared remain challenging. There are two significant gaps that need to addressed: the rest-frame infrared has been untapped for nearby systems due to the lack of wide integral field infrared spectrographs (IFSes), and observations of the distant universe have been limited to small samples from the lack of high angular resolution, highly multiplexed IFSes.

I will discuss two instruments that will directly address these gaps: one recently commissioned, the wide integral field infrared spectrograph (WIFIS), and another recently funded, the Gemini Infrared Multi-object Spectrograph (GIRMOS). WIFIS is currently carrying out an infrared survey of nearby galaxies by studying their stellar populations, star-formation, and kinematics, complementing existing optical surveys such as CALIFA and MaNGA. On the other hand, GIRMOS will be a multi-object IFS that takes advantage of the latest developments in adaptive optics. It will be able to carry out large surveys of the distant universe by simultaneously observing multiple galaxies. It will finally allow the type of work being done for low redshift systems at high redshift.


Monday, October 16, 2017

Imaging the CO snow line in protoplanetary disks

Charlie Qi Harvard-Smithsonian Center for Astrophysics

AST Colloquium

Imaging the CO snow line in protoplanetary disks

Charlie Qi Harvard-Smithsonian Center for Astrophysics
Monday, October 16, 2017

The condensation fronts (snow lines) of water, carbon monoxide (CO) and other abundant volatiles in the midplane of protoplanetary disks affect various aspects of planet formation and composition. Locating the CO snow line directly from millimeter CO data is a challenge since CO gas remains abundant in the warm atmosphere above the disk midplane, also exterior to the CO snow line. Using data from the Submillimeter Array and Atacama Large Millimeter/Submillimeter Array, we have put strong constraints on the location of the CO snow line in the disks. I will also discuss the significant consequences of the CO freeze-out and desorption on the dust evolution and gas chemistry in disks.


Monday, October 2, 2017

Science Policy and You (Yes, You!)

Ashlee Wilkins American Astronomical Society

AST Colloquium

Science Policy and You (Yes, You!)

Ashlee Wilkins American Astronomical Society
Monday, October 2, 2017

As science educators, researchers, communicators, and/or supporters, we cannot deny the connection between science and government. The ability to send missions to Mars, to study star formation in a galaxy, and to model the early universe primarily depends on both government -- i.e., taxpayer -- money and public -- i.e., not just scientist -- support. Scientists can and do engage in work to determine the direction of our field and how society prioritizes science. In this talk, I will focus on ways that policy impacts science, how you, as an individual, can influence policy, and how the American Astronomical Society (AAS) advocates for the astronomical sciences in Washington. 


Monday, September 18, 2017

Highlights of the High Energy Universe from HAWC

Segev BenZvi University of Rochester

AST Colloquium

Highlights of the High Energy Universe from HAWC

Segev BenZvi University of Rochester
Monday, September 18, 2017

During the past decade, the observation of teraelectronvolt (TeV) cosmic rays and gamma rays has opened a new frontier in the study of astrophysical particle accelerators such as super nova remnants, pulsars, microquasars, and active galactic nuclei. This energetic radiation can also be used to explore physics beyond the Standard Model, such as the particle nature of dark matter. Since 2015 the High Altitude Water Cherenkov (HAWC) Observatory has recorded TeV gamma rays and cosmic rays from 2/3 of the sky each day. I will report on recent results from HAWC, including the discovery of nearly 20 new gamma ray sources and high-statistics observations of cosmic rays.


Monday, July 10, 2017

TARdYS an upcoming exoplanet hunter for the southern hemisphere

Surangkhana Rukdee Centro de Astro-Ingeniería UC

AST Colloquium

TARdYS an upcoming exoplanet hunter for the southern hemisphere

Surangkhana Rukdee Centro de Astro-Ingeniería UC
Monday, July 10, 2017

The relatively close habitable zone to the host stars of the very common cool-low mass stars makes M dwarfs attractive for finding habitable planets. Up to date only a few of these stars can be observed by visible high resolution spectrographs since M dwarfs emit the peak of its energy at λ>900 nm in the near infrared region. We optimized a spectrograph for the observation of cool stars in the southern hemisphere where only a few high resolution near infrared spectrographs are available. TARdYS is a high resolution echelle spectrograph to be installed at the Tokyo Atacama Observatory TAO 6.5 m telescope. This spectrograph is a dual fiber fed, white pupil Echelle, which can yield R>50,000 within the spectral range of 0.843-1.117 μm covers Y band. We adopt an echelle R6, 13.33 lines/mm and a VPH 333 lines/mm grating as cross disperser. A Teledyne H1RG detector will be operated in a cryogenic environment cooled to 80K. Our optimization using computer-aided simulation programs results in excellent resolution performance within the diffraction limit even when taking realistic manufacturing and alignment tolerances into account. We will discuss challenges and design decisions of an upcoming exoplanet hunter in the southern hemisphere. The overall instrument system design and ongoing development of TARdYS will be presented.


Monday, April 24, 2017

Quanta Image Sensor: Every Photon Counts

Eric Fossum Dartmouth College

AST Colloquium

Quanta Image Sensor: Every Photon Counts

Eric Fossum Dartmouth College
Monday, April 24, 2017

The Quanta Image Sensor (QIS) is a possible paradigm shift in solid-state image sensors. Conceptually, the QIS counts photons one at a time using small pixels with low full-well capacity and single-photoelectron sensitivity. This binary data is collected and transformed into gray scale images by post-acquisition digital image processing. In recent years, the QIS has moved from concept to experimental devices. A 1Mpixel QIS has been designed and fabricated in a commercial stacked, backside-illuminated CMOS image sensor 65/45nm node process. The device, with 1.1um shared-readout pixel pitch, has been shown to have read noise as low as 0.172e- rms at room temperature without the use of avalanche multiplication, and is successfully readout at 1040fps using a cluster-parallel readout architecture. Each binary bit represents the detection or absence of a photoelectron.

The QIS technology is evolved from the CMOS image sensor currently incorporated into billions of cameras each year. In a preamble to the QIS part of the talk, the invention and development of the CMOS image sensor technology at the NASA Jet Propulsion Laboratory at Caltech, and by the spinoff company Photobit will be discussed.


Monday, April 10, 2017

The Intricate Role of Cold Gas and Dust in Galaxy Evolution at Early Cosmic Epochs

Dominik A. Riechers Cornell University

AST Colloquium

The Intricate Role of Cold Gas and Dust in Galaxy Evolution at Early Cosmic Epochs

Dominik A. Riechers Cornell University
Monday, April 10, 2017

Dusty starburst galaxies at very high redshift represent an important phase in the early evolution of massive galaxies. They typically represent large-scale, gas-rich major mergers that trigger intense, short-lived bursts of star formation, which consume most of the available gas and drive the morphological transition to spheroids. At early cosmic epochs, these hyper-luminous galaxies commonly trace regions of high galaxy overdensity, and may be directly related to the formation of galaxy clusters and their giant central ellipticals. Molecular and atomic gas plays a central role in our understanding of the nature of these often heavily obscured distant systems. It represents the material that stars form out of, and its mass, distribution, excitation, and dynamics provide crucial insight into the physical processes that support the ongoing star formation and stellar mass buildup. I will discuss the most recent progress in studies of the cold gas content of dusty starburst galaxies at high redshift, back to the first billion years of cosmic time using CARMA, the Jansky Very Large Array, the Plateau de Bure interferometer, and the Atacama Large (sub)Millimeter Array (ALMA). I will also highlight our recent successful first detections of the interstellar medium in "normal" (~L*) galaxies at z>5 with ALMA, and discuss the impact of our findings on future studies back to even earlier epochs.

 


Monday, March 27, 2017

New Approaches to Dark Matter

Justin Khoury University of Pennsylvania

AST Colloquium

New Approaches to Dark Matter

Justin Khoury University of Pennsylvania
Monday, March 27, 2017

In this talk I will discuss a novel theory of superfluid dark matter. The scenario matches the predictions of the Lambda-Cold-Dark-Matter (LambdaCDM) model on cosmological scales while simultaneously reproducing the MOdified Newtonian Dynamics (MOND) empirical success on galactic scales. The dark matter and MOND components have a common origin, as different phases of a single underlying substance. This is achieved through the rich and well-studied physics of superfluidity. The framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): due to the higher velocity dispersion in clusters, and correspondingly higher temperature, the dark matter in clusters is either in a mixture of superfluid and normal phases, or fully in the normal phase. The model makes various observational predictions that distinguishes it from both LambdaCDM and standard MOND. In the last part of the talk, I will discuss an on-going attempt at explaining cosmic acceleration as yet another manifestation of dark matter superfluidity.


Monday, February 27, 2017

Unveiling Black Hole Growth Over Cosmic Time

Stephanie LaMassa Space Telescope Science Institute

AST Colloquium

Unveiling Black Hole Growth Over Cosmic Time

Stephanie LaMassa Space Telescope Science Institute
Monday, February 27, 2017

Supermassive black holes, millions to billions of times the mass of our Sun, live in the center of every massive galaxy. When they grow via the process of accretion, they are observed as Active Galactic Nuclei (AGN). In addition to being among the most energetic sources in the Universe, AGN seemed to be intrinsically linked to the galaxies in which they reside. By surveying regions of the sky, we can discover AGN from early cosmic times to the present day, thereby learning about supermassive black hole growth and evolution and the role they may play in shaping their host galaxies. Currently, we are missing an important piece of the puzzle in AGN evolution - luminous obscured black hole growth. To this end, I am leading a wide area X-ray survey: by probing a large volume of the Universe, a representative sample of rare objects are detected, and X-rays pierce through dust that obscures optical light, recovering AGN missed by optical surveys. By executing this survey in the Stripe 82 region of the Sloan Digital Sky Survey which contains rich multi-wavelength coverage, we have the ancillary data necessary to characterize the AGN and their host galaxies. In this talk, I will give an overview of this “Stripe 82X" survey, summarize the properties of the objects we have detected thus far, discuss what we are planning to learn from this dataset in the coming years, and how we can these data to develop best-effort practices to push into new discovery space with upcoming missions like JWST, WFIRST, LSST, and eROSITA. I will highlight a peculiar source I discovered in this survey which has now become a burgeoning subfield in AGN physics, providing unique insight into AGN lifetimes and black hole fueling.


Monday, February 13, 2017

Modeling Baryonic Physics in Galaxy Clusters

Erwin Lau Yale University

AST Colloquium

Modeling Baryonic Physics in Galaxy Clusters

Erwin Lau Yale University
Monday, February 13, 2017

Galaxy clusters play an important role in modern precision cosmology. As the most massive virialized objects in the universe, their abundance depends sensitively on cosmological parameters. However, uncertainties in galaxy cluster physics pose serious challenges to using forthcoming observations to make advances in cosmology with galaxy clusters. 
In this talk, I will highlight how we can improve our understanding of galaxy cluster physics with the state-of-the-art numerical simulations and semi-analytical modelling. In particular,  I will present results from the "Omega500" simulation, a high-resolution hydrodynamic simulation suite of galaxy cluster formation that follows the evolution of dark matter and baryons in a realistic cosmological setting. I will also outline upcoming challenges in the computational modelling of major physical processes in galaxy clusters, and how we can address them in anticipation of upcoming multi-wavelength cluster surveys in the next decade. 
 

Monday, January 30, 2017

A Galaxy-Scale Fountain of Cold Molecular Gas Pumped by a Black Hole

Grant Tremblay Yale University

AST Colloquium

A Galaxy-Scale Fountain of Cold Molecular Gas Pumped by a Black Hole

Grant Tremblay Yale University
Monday, January 30, 2017

A new ALMA observation of the cool core brightest cluster galaxy in Abell 2597 reveals that a supermassive black hole can act much like a mechanical pump in a water fountain, driving a convective flow of molecular gas that drains into the black hole accretion reservoir, only to be pushed outward again in a jet-driven outflow that then rains back toward the galaxy center from which it came. The ALMA data reveal "shadows" cast by giant molecular clouds falling on ballistic trajectories towards the black hole in the innermost hundred parsecs of the galaxy, manifesting as deep redshifted continuum absorption features.  The black hole accretion reservoir, fueled by these infalling cold clouds, powers an AGN that drives a  jet-driven molecular outflow in the form of a 10 kpc-scale, billion solar mass expanding molecular bubble. HST reveals that the molecular shell is permeated with young stars, perhaps triggered in situ by the jet.  Buoyant X-ray cavities excavated by the propagating radio source may further uplift the molecular filaments, which are observed to fall inward toward the center of the galaxy from which they came, presumably keeping the fountain long-lived. I will discuss this specific result in the larger context of galaxies as a whole, as the results show that cold molecular gas can couple to black hole growth via both feedback and feeding, in alignment with "cold chaotic accretion" models for the regulation of star formation in galaxies. 


Monday, December 12, 2016

Opening the gravitational wave universe: the physics behind a new type of astronomy

Shelia Dwyer Caltech

AST Colloquium

Opening the gravitational wave universe: the physics behind a new type of astronomy

Shelia Dwyer Caltech
Monday, December 12, 2016

Hosted by the School of Physics & Astronomy and the Center for Computational Relativity and Gravitation

With the first direct detection of gravitational waves, the LIGO detectors have opened a new field of astrophysics, discovered a new class of massive stellar mass black holes, and enabled tests of general relativity.  To make these discoveries, we built the most sensitive displacement meters yet, measuring displacements of one thousandth of a proton diameter over a 4 kilometer baseline.  This talk will focus on the physics of the ground breaking detectors, and the possibilities for extending their reach.  One of the most promising techniques for improving the sensitivity is the use of squeezed states to reduce quantum noise.  l will describe a test of squeezing in the LIGO interferometers, and implications for the permanent application of squeezing in Advanced LIGO over the next few years.  Because gravitational wave detectors measure amplitude rather than power, improvements in sensitivity from squeezing, cryogenic operation and new optical materials have the potential to dramatically increase the volume of the universe which can be surveyed.  In a new and larger facility, LIGO style detectors could observe compact object binaries from the earliest periods of star formation, making complete surveys at distances difficult to observe with optical telescopes.  


Monday, December 5, 2016

The Future of Gravitational Wave Interferometers

Jax Sanders Syracuse University

AST Colloquium

The Future of Gravitational Wave Interferometers

Jax Sanders Syracuse University
Monday, December 5, 2016

Hosted by the School of Physics & Astronomy and the Center for Computational Relativity and Gravitation

The recent detection of gravitational waves from binary black hole mergers marks the beginning of the field of gravitational wave astronomy. New and more sensitive techniques will be required to continue expanding our understanding of the universe through gravitational waves. Current research and development efforts range from surpassing the standard quantum limit using squeezed states, to improving thermal noise at the frontiers of the material science of optical coatings, to the conceptual design of new interferometer topologies. These noise reduction efforts will increase the sensitivity of the detectors, allowing the measurement of smaller effects and extending our reach to cosmological scales.


Monday, November 21, 2016

The radial acceleration relation: linking baryons and dark matter in galaxies

Federico Lelli Case Western Reserve University

AST Colloquium

The radial acceleration relation: linking baryons and dark matter in galaxies

Federico Lelli Case Western Reserve University
Monday, November 21, 2016

The flat rotation curves of spiral galaxies provided clear evidence for mass discrepancies in galactic systems, but the nature of dark matter (DM) still remains elusive. I will describe recent results from the Spitzer Photometry and Accurate Rotation Curves (SPARC) dataset: the largest collection of HI rotation curves currently available for late-type galaxies (spirals and irregulars). New Spitzer photometry at 3.6 um provides the closest proxy to the stellar mass, allowing precise estimates of the baryonic gravitational field at every radii (g_bar). We find that the observed acceleration correlates with g_bar over 4 dex, implying a close link between baryons and DM in galaxies. This radial acceleration relation coincides with unity (no DM) at high g_bar but systematically deviates below a critical acceleration scale. The observed scatter is remarkably small, even when DM dominates at low g_bar. Early-type galaxies (ellipticals, lenticulars, and dwarf spheroidals) follow the same relation as late-type galaxies. The radial acceleration relation is tantamount to a "Kepler Law" for galactic systems: when the baryonic contribution is measured, the rotation curve follows, and vice versa. I will discuss possible interpretations within the standard LCDM cosmology as well as alternative theories.


Monday, November 7, 2016

Studying planet formation processes with molecular spectroscopy

Colette Salyk Vassar College

AST Colloquium

Studying planet formation processes with molecular spectroscopy

Colette Salyk Vassar College
Monday, November 7, 2016

As our understanding of the solar system and exoplanetary systems continues to grow, our view of planet formation processes must expand to accommodate the incredibly diversity of formation outcomes.  I will focus this talk on my favorite technique for studying planet formation processes in action - molecular spectroscopy.  I will review the techniques of molecular spectroscopy and discuss how they can be used to tackle key questions about planet formation, including: Where does water freeze, and does this correspond with giant planet formation?  Are there spectroscopic signatures of disk evolution, or the presence of planets?  What factors determine the final chemical make-up of a  planet?  I will highlight some of the incredible progress that has been made on answering these questions in recent years, and provide updates on ongoing projects, including several involving undergraduate students.


Monday, October 24, 2016

Illuminating the Black Hole – Galaxy Connection with CANDELS

Dale Kocevski Colby College

AST Colloquium

Illuminating the Black Hole – Galaxy Connection with CANDELS

Dale Kocevski Colby College
Monday, October 24, 2016

Supermassive black holes, and the active galactic nuclei (AGN) that they power, are thought to play an integral role in the evolution of galaxies by acting to regulate, and eventually suppress, the star formation activity of their host galaxies.  I will discuss recent efforts to test this proposed connection by studying the demographics of galaxies undergoing active black hole growth.  In particular, I will highlight recent results from the CANDELS survey, whose panchromatic Hubble ACS and WFC3 imaging is now allowing us to characterize the morphologies and stellar populations of thousands of AGN hosts out to z=2, the era when star formation activity and black hole growth in the Universe are at their peak.  I will discuss what CANDELS is currently revealing about the mechanisms that fuel AGN activity at this epoch and the connection between black hole growth and the emergence of the first generation of passive galaxies in the Universe.


Monday, October 10, 2016

Glimpses of futuristic cosmology: relativistic effects and spectral maps

Rupert Croft Carnegie Mellon University

AST Colloquium

Glimpses of futuristic cosmology: relativistic effects and spectral maps

Rupert Croft Carnegie Mellon University
Monday, October 10, 2016

In the next 10 years, the number of galaxies with measured redshifts will increase into the tens of millions. Beyond this, mapping the Universe will be done not by detecting individual galaxies, but by recording spectral information for the entire sky. Both of these developments will make possible new ways to pin down the nature of dark matter, dark energy and gravity. It has not been widely realized, however that some new types of exploration can begin with presently available data. I will describe how to measure Special and General Relativistic effects distorting the observed large-scale structure of the Universe. These include the gravitational redshift (first seen in Earth-bound laboratories in 1960) and relativistic beaming, which is now detectable on the scales of galaxies and beyond. I will present results from hydrodynamic simulations as well as some preliminary measurements from galaxy survey data. I will then move on to spectral intensity mapping, a technique which promises to make truly inclusive surveys of the Universe. I will present the first measurements of  the large-scale structure of the cosmos made using optical line intensity, and show how the results are suprising in the context of our standard cosmological model. I will discuss how lessons learned during the analysis can be applied to future experiments, and motivate specialized instruments.

Monday, September 26, 2016

Bridging interferometry and astrophysics: noise and the future of gravitational wave astronomy

Jess McIver Caltech

AST Colloquium

Bridging interferometry and astrophysics: noise and the future of gravitational wave astronomy

Jess McIver Caltech
Monday, September 26, 2016

About one year ago, the Advanced LIGO detectors sensed the passing of gravitational wave signal GW150914 from the merger of two black holes, each roughly 30 solar masses. This discovery ushered in a new era of gravitational wave astronomy. It was the first direct detection of gravitational waves and provided evidence of black holes with masses never before observed. Roughly three months later, the LIGO detectors observed a second binary black hole merger, GW151226, with strong evidence of black hole spin.
This talk will focus on the interface between gravitational wave astrophysics and instrumentation. The LIGO detectors have unprecedented sensitivity to spacetime strain, but the interferometer data are not perfectly clean. The LIGO Scientific Collaboration has a strong history of detector characterization work that studies the causes of noise artifacts in the data and their effect on the recovery of astrophysical signals. I will show the impact of detector characterization efforts on searches for compact binary coalescences during Advanced LIGO's first observing run. I will also illustrate that noise characterization will become increasingly important, particularly for extracting the astrophysical parameters of detected sources, as LIGO improves in sensitivity and the global gravitational wave community fields an increasing rate of detections.

Monday, May 9, 2016

Inside-Out Planet Formation

Jonathan C. Tan University of Florida

AST Colloquium

Inside-Out Planet Formation

Jonathan C. Tan University of Florida
Monday, May 9, 2016

The Kepler-discovered systems with tightly-packed inner planets (STIPs), typically with several planets of Earth to super-Earth masses on well-aligned, sub-AU orbits may host the most common type of planets in the Galaxy. They pose a great challenge for planet formation theories, which fall into two broad classes: (1) formation further out followed by migration; (2) formation in situ from a disk of gas and planetesimals. I review the pros and cons of these classes, before focusing on a new theory of sequential in situ formation from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles," drifting inward via gas drag. Pebbles first collect at the pressure trap associated with the transition from a magnetorotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an Earth to super-Earth-mass planet directly or induces gradual planet formation via core accretion. The planet continues to accrete until it becomes massive enough to isolate itself from the accretion flow via gap opening. The process repeats with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. I discuss the theory’s predictions for planetary masses, relative mass scalings with orbital radius, and minimum orbital separations, and their comparison with observed systems. Finally I speculate about potential causes of diversity of planetary system architectures, i.e. STIPs versus Solar System analogs.

Monday, May 2, 2016

Unveiling the dark side of the Universe

Priya Natarajan Yale University

AST Colloquium

Unveiling the dark side of the Universe

Priya Natarajan Yale University
Monday, May 2, 2016

Dark matter and Dark Energy, the enigmatic dominant constituents of our Universe shape the properties of structures. However, their essential nature remains unknown.
Gravitational lensing, the bending of light by matter predicted by Einstein's Theory of General Relativity offers a powerful probe of both dark matter and dark energy. Deploying
clusters of galaxies as gravitational lenses a viewed by the Hubble Space Telescope we have many interesting new results - I will present a status report of recent progress in 
this talk.

Monday, April 25, 2016

Dusty Universe

Asantha Cooray University of California, Irvine

AST Colloquium

Dusty Universe

Asantha Cooray University of California, Irvine
Monday, April 25, 2016

Dr. Cooray will summarize the scientific case for studying the universe and Far-Infrared and sub-millimeter wavelengths. She will present results from Herschel,  summarize on going plans for ground-based instruments, and outline the ongoing Far-Infared Surveyor study facilitated by NASA for 2020 Decadal Surveyor.


Monday, March 21, 2016

Galaxy Mergers on FIRE: Mapping Star Formation

Jorge Moreno Cal Poly Pomona

AST Colloquium

Galaxy Mergers on FIRE: Mapping Star Formation

Jorge Moreno Cal Poly Pomona
Monday, March 21, 2016

Galaxy mergers and interactions are responsible for generating bursts of star formation, for changing galactic morphology in dramatic ways, and for triggering single and dual active galactic nuclei. In this talk, I will unveil the very first results from a novel suite of high-resolution galaxy merger simulations, based on the “Feedback In Realistic Environments” (FIRE) model. This model treats energy and momentum-driven feedback from young stars and SN explosions explicitly, which acts directly on resolved star-forming clouds within the ISM. Moreover, this framework relies on a new meshless Lagrangian hydro code, GIZMO, which solves many problems associated with older solvers. Our first work focuses on the spatial localization of star formation. In particular, we confirm results from previous work: galaxy-galaxy interactions enhance nuclear star formation, and suppress it at large galacto-centric radii (Moreno et al. 2015). However, two major differences are found. First, star-formation enhancement and suppression are not as dramatic as in older models. Secondly, the interaction-induced nuclear starburst has a larger spatial extent. These differences are a reflection of the fact that, in our new models, non-axisymmetric gravitational torques are not as effective at driving fuel into the central regions as in older sub-grid based models. This suite of merger simulations is ideal for making predictions for, and interpreting results from, observations by new-generation integral field spectroscopic surveys, such as CALIFA, MaNGA and HECTOR.


Monday, March 7, 2016

New astronomical projects from Japan: TAO and the Tomo-e Gozen Camera

Mamoru Doi University of Tokyo

AST Colloquium

New astronomical projects from Japan: TAO and the Tomo-e Gozen Camera

Mamoru Doi University of Tokyo
Monday, March 7, 2016

The Institute of Astronomy, part of the University of Tokyo's School of Science, is currently operating two observatories: the Tokyo Atacama Observatory (TAO) in Chile, and the Kiso Observatory in Nagano, Japan.  The goal of TAO is to operate a 6.5-m optical-infrared telescope at Cerro Chajnantor in Chile (elevation 5,640m), the world's highest site for an astronomical observatory. A pathfinder telescope, the miniTAO 1.0-m telescope, has been operating there since 2009, and we can confirm that it opens new atmospheric windows in the mid-infrared. I will review the current status of the TAO project as well as early results from miniTAO.
At the Kiso observatory, we are developing a new wide-field imager, the Tomo-e Gozen Camera, which is going to use 84 CMOS sensors. I will show some early results from a prototype camera with 8 CMOS sensors, called Tomo-e PM.

Monday, February 29, 2016

The Biggest Blowhards: Windy Supermassive Black Holes

Sarah Gallagher Western University

AST Colloquium

The Biggest Blowhards: Windy Supermassive Black Holes

Sarah Gallagher Western University
Monday, February 29, 2016

Supermassive black holes reside in the centers of every massive galaxy. In relatively brief spurts, black holes grow as luminous quasars through the infall of material through an accretion disk. Remarkably, the light from the accretion disk can outshine all of the stars in the host galaxy by a factor of a thousand, and this radiation can also drive energetic mass outflows. Mass ejection in the form of winds or jets appears to be as fundamental to quasar activity as accretion, and can be directly observed in many objects with broadened and blue-shifted UV emission and absorption features. A convincing argument for radiation pressure driving this ionized outflow can be made within the dust sublimation radius. Beyond, radiation pressure is still important, but high energy photons from the central engine can now push on dust grains. This physics underlies the dusty wind picture for the putative obscuring torus. I'll describe our model of the dusty wind and evaluate its successes and shortcomings in accounting for observed properties of quasars such their mid-infrared power, fractions of hidden objects, and column densities of important ions.

Monday, December 7, 2015

Cosmological Simulations of Galaxy Formation and Evolution

Lars Hernquist Harvard-Smithsonian Center for Astrophysics

AST Colloquium

Cosmological Simulations of Galaxy Formation and Evolution

Lars Hernquist Harvard-Smithsonian Center for Astrophysics
Monday, December 7, 2015

A predictive theory of galaxy formation remains elusive, even after more than 50 years of dedicated effort by many renowned astrophysicists.  The problem of galaxy formation is made difficult by the large range in scales involved and the many non-linear physical processes at work.  In this talk, I describe a new generation of numerical models designed to overcome these difficulties based on novel schemes for solving the fluid equations on a moving mesh. Initial results from this study provide insight into many aspects of galaxy assembly and the relationship between galaxies and cosmologically-distributed baryons.


Monday, November 23, 2015

Dark Energy Spectroscopic Instrument

Peter Nugent University of California, Berkeley

AST Colloquium

Dark Energy Spectroscopic Instrument

Peter Nugent University of California, Berkeley
Monday, November 23, 2015

The Dark Energy Spectroscopic Instrument (DESI) will measure the effect of dark energy on the expansion of the universe.  It will obtain optical spectra for tens of millions of galaxies and quasars, constructing a 3-dimensional map spanning the nearby universe to 10 billion light years over 14,000 square degrees of sky.  DESI’s key project goals are to (a) probe the effects of dark energy on the expansion history using Baryon Acoustic Oscillations and (b) measure the gravitational growth history using redshift-space distortions. DESI will be conducted on the Mayall 4-meter telescope at Kitt Peak National Observatory starting in 2018. Here I will describe the overall design of the experiment, its current status and the massive photometric targeting surveys being carried out now in preparation for DESI. 

Monday, October 19, 2015

Successes and failures of LambdaCDM and its alternatives

Benoit Famaey Universite de Strasbourg

AST Colloquium

Successes and failures of LambdaCDM and its alternatives

Benoit Famaey Universite de Strasbourg
Monday, October 19, 2015

While there is indisputable observational evidence for a new degree of freedom behaving as a collisionless fluid of particles on large scales, i.e. dark matter, there is no such solid evidence on galaxy scales. On the contrary, the current LambdaCDM model of cosmology is plagued with numerous challenges at these scales, which we review here. These small-scale-problems of cosmology include the mismatch between the predicted and much smaller observed number of satellite galaxies in the Local Group (missing satellite problem), the shape of the inner dark matter distribution in galaxies (core-cusp problem), the concentration of sub-halo potential in satellite galaxies (too-big-to-fail problem), or the phase-space distribution of satellite galaxies (satellite plane problem). These challenges might not directly indicate a failure of the standard model of cosmology since, until recently, baryonic physics has largely been ignored in the simulations, but might be able to alleviate many of the problems. However, we argue that the observational evidence for an intimate connection between the baryonic surface density and the total gravitational field in spiral galaxies presents a severe fine-tuning problem for any particle dark matter interpretation of galactic mass discrepancies. On the other hand, it is obvious that any alternative to the standard model of cosmology must also, in fine, reproduce the successes of this model on large scales, where it is so well-tested that it presents by itself a challenge to any such alternative.

Monday, October 12, 2015

Exoplanet Climatology: The Next Era of Habitable-planet Hunting

Aomawa Shields UCLA/Harvard

AST Colloquium

Exoplanet Climatology: The Next Era of Habitable-planet Hunting

Aomawa Shields UCLA/Harvard
Monday, October 12, 2015

 The identification of an exoplanet receiving the amount of incident radiation from its host star to lie within the star¹s habitable zone has been the primary step taken in classifying a planet as "potentially habitable". However, recent research and the history of our own planet has shown that many factors and processes other than orbital distance can affect climate and planetary habitability. Discovering a planet in the habitable or "Goldilocks" zone is therefore but a first step in the process of finding the next planet where life can survive. To identify habitable exoplanets, it is important to understand how both orbital and atmospheric properties affect the climate of exoplanets, and how these climatic effects might change for different stellar and planetary environments. I will share results from work performed using a hierarchy of models to simulate planets orbiting stars of different spectral types and with varied orbital architectures, and discuss the implications of these results for planetary climate and habitability. My methods can be used to assess the possible climates of potentially habitable planets as they are discovered. This work ushers in a new era of utilizing observational and theoretical techniques together to target the next planet where life exists.

Monday, October 5, 2015

Star Formation in the Midst of Upheaval - Goings On in the Centers of Rich Clusters of Galaxies

Stefi Baum University of Manitoba

AST Colloquium

Star Formation in the Midst of Upheaval - Goings On in the Centers of Rich Clusters of Galaxies

Stefi Baum University of Manitoba
Monday, October 5, 2015

How and where does star formation occur in elliptical galaxies sitting at the centers of rich clusters of galaxies in the midst of cooling cores of hot-xray gas, mergers of galaxies, and powerful outflowing jets emanating from a central black hole? Recent ALMA (millimeter),  HST (ultraviolet) and Ground Based (Optical) observations reveal more detailed information on the interplay of energetics, activity and star formation in these unique environments.


Sunday, September 27, 2015

RIT Observatory: Open House


AST Colloquium

RIT Observatory: Open House

Sunday, September 27, 2015


Monday, September 21, 2015

Rings and Radial Waves in the Milky Way's Stellar Disk

Heidi Newberg Rensselaer Polytechnic Institute

AST Colloquium

Rings and Radial Waves in the Milky Way's Stellar Disk

Heidi Newberg Rensselaer Polytechnic Institute
Monday, September 21, 2015

Abstract: I will show that there is an asymmetry in the main sequence star counts on either side of the Galactic plane, as one looks towards the Galactic anticenter. This can be explained if the disk of the Milky Way oscillates up and down. This oscillation could provide an explanation for the Monoceros Ring, and also for the TriAndromeda Stream (or Ring). The implication is that the stellar disk extends out to at least 25 kpc from the Galactic center - much farther than the canonical 15 kpc that is typically quoted. The oscillations are aligned with the spiral arms of the Milky Way, and are plausibly consistent with previous predictions for disk ringing due to a Sagittarius dwarf-sized galaxy plunging through the disk.


Monday, May 11, 2015

What neutrinos and magnetic turbulence do to nuclear-density toroidal stars and disks: some numerical relativity models

Matthew Duez Washington State University

AST Colloquium

What neutrinos and magnetic turbulence do to nuclear-density toroidal stars and disks: some numerical relativity models

Matthew Duez Washington State University
Monday, May 11, 2015


Monday, May 4, 2015

RR Lyrae Stars in M31, M32 and M33

Ata Sarajedini University of Florida

AST Colloquium

RR Lyrae Stars in M31, M32 and M33

Ata Sarajedini University of Florida
Monday, May 4, 2015


Monday, April 27, 2015

Gas in Local Dwarf Galaxies

Jana Grcevich American Museum of Natural History

AST Colloquium

Gas in Local Dwarf Galaxies

Jana Grcevich American Museum of Natural History
Monday, April 27, 2015


Monday, April 20, 2015

Scrutinizing the Relationship Between Galaxies and Supermassive Black Holes

Jillian Bellovary Vanderbilt University

AST Colloquium

Scrutinizing the Relationship Between Galaxies and Supermassive Black Holes

Jillian Bellovary Vanderbilt University
Monday, April 20, 2015


Monday, April 13, 2015

[Re]Exploring the Universe with [NEO]WISE

Edward (Ned) Wright UCLA

AST Colloquium

[Re]Exploring the Universe with [NEO]WISE

Edward (Ned) Wright UCLA
Monday, April 13, 2015


Friday, March 20, 2015

Observable Signatures of Neutron Star Mergers

Brian Metzger Columbia University

AST Colloquium

Observable Signatures of Neutron Star Mergers

Brian Metzger Columbia University
Friday, March 20, 2015


Monday, March 16, 2015

Bose-Einstein Condensate Axion Dark Matter

Chanda Prescod-Weinstein MIT

AST Colloquium

Bose-Einstein Condensate Axion Dark Matter

Chanda Prescod-Weinstein MIT
Monday, March 16, 2015


Monday, December 1, 2014

"Tension" in the Extragalactic Distance Scale and "New Physics": Ending the Debate over the Hubble Constant

Barry Madore Carnegie Observatories

AST Colloquium

"Tension" in the Extragalactic Distance Scale and "New Physics": Ending the Debate over the Hubble Constant

Barry Madore Carnegie Observatories
Monday, December 1, 2014


Monday, November 24, 2014

Determining the Cause of Cosmological Acceleration with Large Astronomical Surveys

Andrew Zentner University of Pittsburgh

AST Colloquium

Determining the Cause of Cosmological Acceleration with Large Astronomical Surveys

Andrew Zentner University of Pittsburgh
Monday, November 24, 2014


Friday, November 21, 2014

Are exoplanets really tidally synchronized?

Jeremy Leconte University of Toronto (CITA)

AST Colloquium

Are exoplanets really tidally synchronized?

Jeremy Leconte University of Toronto (CITA)
Friday, November 21, 2014


Thursday, December 1, 2016

Galactic Ecology: Where Have All the Baryons Gone?

Crystal Martin Department of Physics University of California, Santa Barbara

Women in Science

Galactic Ecology: Where Have All the Baryons Gone?

Crystal Martin Department of Physics University of California, Santa Barbara
Thursday, December 1, 2016

Galaxies are surprisingly deficient in normal matter. Compared to the universe as a whole, the ratio of normal matter to dark matter is low in galaxies. Recent work strongly suggests that these missing baryons reside in a diffuse gas surrounding galaxies.  Professor Martin will describe why astrophysicists believe this halo gas is very dynamic. She will present the latest results on measurements of gas flows between galaxies and this circumgalactic medium. The results have important implications for how the star formation rate in galaxies is regulated as well as the enrichment history of interstellar and intergalactic gas.


Wednesday, October 19, 2016

From Career Pathways to Physics/Astronomy Trivia

Brad Conrad American Institute of Physics/SPS and Sigma Pi Sigma

Seminar

From Career Pathways to Physics/Astronomy Trivia

Brad Conrad American Institute of Physics/SPS and Sigma Pi Sigma
Wednesday, October 19, 2016

Come learn about physics and astronomy career options, topics such as how to fail an interview, why networking is so important, and compete in physics trivia with the Director of the Society of Physics Students and Sigma Pi Sigma! Alum Dr. Brad R. Conrad will discuss how to make the most of your time at RIT and teach a few skills that can help you along the way.

 Bio: Dr. Brad R. Conrad is the Director of the Society of Physics Students (SPS) and Sigma Pi Sigma (ΣΠΣ), the physics honors society, at the American Institute of Physics (AIP) in College Park, MD. In addition to leading SPS National initiatives, he works to support and promote undergraduate Physics and Astronomy majors and their mentors. Before becoming director, Dr. Conrad was an Associate Professor of Physics and Astronomy at Appalachian State University, an NRC postdoctoral fellow at the National Institute of Standards, earned his Ph.D. in Physics at the University of Maryland, College Park MD, in the area of condensed matter/surface physics, and earned his Bachelor’s degree from Rochester Institute of Technology in Physics.


Wednesday, May 6, 2015

From Exoplanets to Exoworlds

David Rosario Max Planck Institute for Extraterrestrial Physics

Seminar

From Exoplanets to Exoworlds

David Rosario Max Planck Institute for Extraterrestrial Physics
Wednesday, May 6, 2015


Friday, May 1, 2015

How Cosmic Collisions Shape the Universe

Jeyhan Kartaltepe National Optical Astronomy Observatory

Seminar

How Cosmic Collisions Shape the Universe

Jeyhan Kartaltepe National Optical Astronomy Observatory
Friday, May 1, 2015


Wednesday, April 29, 2015

From Exoplanets to Exoworlds

Kevin Stevenson University of Chicago

Seminar

From Exoplanets to Exoworlds

Kevin Stevenson University of Chicago
Wednesday, April 29, 2015


Monday, October 17, 2016

Assessment: The silent killer of learning

Eric Mazur Harvard University

Distinguished Speaker

Assessment: The silent killer of learning

Eric Mazur Harvard University
Monday, October 17, 2016

Why is it that stellar students sometimes fail in the workplace while dropouts succeed? One reason is that most, if not all, of our current assessment practices are inauthentic. Just as the lecture focuses on the delivery of information to students, so does assessment often focus on having students regurgitate that same information back to the instructor. Consequently, assessment fails to focus on the skills that are relevant in life in the 21st century. Assessment has been called the "hidden curriculum" as it is an important driver of students' study habits. Unless we rethink our approach to assessment, it will be very difficult to produce a meaningful change in education.


Monday, December 7, 2015

Vibrations from the Big Bang

Jamie Bock California Institute of Technology

Distinguished Speaker

Vibrations from the Big Bang

Jamie Bock California Institute of Technology
Monday, December 7, 2015

Moments after the Big Bang, our observable universe underwent a violent growth spurt called inflation. The inflationary expansion flung apart the observable universe from a causally-connected sub-atomic volume, and established a primordial spectrum of scalar perturbations that led to the temperature anisotropies observed in the cosmic microwave background. Dr. Bock's team has been making precise degree-scale polarization measurements of the CMB from the south pole with the BICEP/Keck series of experiments in search of a distinctive ‘B-mode’ pattern, a hallmark of tensor perturbations associated with a background of gravitational waves generated by inflation. Dr. Bock will present our latest results that incorporate multi-band information from the Planck satellite and new Keck Array data at 95 and 150 GHz. He will also discuss prospects from new data and improved measurements coming in the near future.

Supported by the John Wiley Jones Science Endowment Fund
To request Interpreting Services, please visit myAccess.rit.edu.


Friday, February 12, 2016

Observation of Gravitational Waves from a Binary Black Hole Merger

John Whelan, Richard O'Shaughnessy, Carlos Lousto, and Manuella Campanelli CCRG

CCRG seminar

Observation of Gravitational Waves from a Binary Black Hole Merger

John Whelan, Richard O'Shaughnessy, Carlos Lousto, and Manuella Campanelli CCRG
Friday, February 12, 2016

Abstract:
LIGO has just reported three discoveries: the first direct detection of gravitational waves; the discovery of a binary black hole; and the observation of gravitational waves from this binary's coalescence,  in excellent agreement with Einstein's theory of gravity.  In a presentation and panel discussion, RIT scientists John Whelan, Richard O'Shaughnessy, Carlos Lousto, and Manuella Campanelli -- all members of RIT's Center for Computational Relativity and Gravitation --  discuss the significance of these findings.

For more information see the attached summary PDF, and the summaries avaialble at
  -   http://ligo.org/science/outreach.php
  -   https://losc.ligo.org/events/GW150914/


Friday, September 11, 2015

Listening for Deep Understanding of Energy

DR. MICHAEL WITTMANN University of Maine

CASTLE Seminar

Listening for Deep Understanding of Energy

DR. MICHAEL WITTMANN University of Maine
Friday, September 11, 2015

How do people understand energy? In studying teaching and learning in physics, researchers have primarily used two methods to understand content understanding: individual interviews or large-class surveys. Sometimes it's not possible to do either, given constraints on the population being interviewed, or a small enough population that the statistics from surveys won't tell us much. In the Maine Physical Sciences Partnership, we have addressed this problem in two ways when working with the population of middle school physical science teachers. We have asked them survey questions on an annual basis and can use the changes in their responses to investigate their thinking about energy. We have also observed and analyzed their interactions in large-group discussion during professional development activities. By listening differently, we're able to learn about their knowledge of the deep structure of the physics.


Rochester Institute of Technology College of Science