Physics Colloquium: Quantum trajectories and stochastic thermal machines

Physics Colloquium
Quantum trajectories and stochastic thermal machines

Mr. Gabriel Landi
Associate Professor
University of Rochester

Abstract:
In this talk I will discuss the recent progress in describing the thermodynamics of quantum trajectories. The problem will be motivated with a discussion of cooling down a superconducting qubit using an absorption refrigerator. We provide an overview of how to use the toolbox of quantum instruments to provide an extremely general formulation of the problem. And we specialize it to the important case of quantum jumps. In both cases, we introduce the basic ideas behind full counting statistics, which is used to connect quantum dynamics to experimental measurement outcomes. We introduce the notion of stochastic excursions, and how it can be used to understand different mechanisms that contribute to current fluctuations. Finally, we introduce new results from our group on the description of feedback protocols based on quantum trajectories. We highlight a very general formalism, based on generic quantum instruments, and then discuss how these can be specialized to devise novel feedback strategies based on quantum jump detection. These concepts will be illustrated with examples from superconducting qubits, transport across quantum dots and atomic masers.

Speaker Bio:
Professor Landi is an Associate Professor in the Department of Physics and Astronomy of the University of Rochester, and an editor for Physical Review Research. Previously he was an assistant professor in Brazil, first at UFABC (2013-2016) then at the University of São Paulo (2016-2022). Professor Landi heads the Quantum Thermodynamics and Quantum Transport group (QT2), which does theory research at the boundary between quantum information sciences and statistical physics. He is a specialist in the field of open quantum systems, with applications to quantum thermodynamics, quantum transport and quantum metrology. His group has contributed extensively to the reformulation of the laws of thermodynamics in the presence of quantum coherence, as well as to the understanding of continuously measured quantum systems, and the connection between classical data and the underlying quantum dynamics.

Intended Audience:
Beginners, undergraduates, graduates. Those with interest in the topic.

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