Graduate Seminar: Dr. Ryan Bennink - Efficient Verification of Quantum States Using Just a Little Quantum Computation

Joint Computer Engineering and Electrical and Microelectronics Engineering Graduate Seminar

Efficient Verification of Quantum States Using Just a Little Quantum Computation

Presented by
Dr. Ryan Bennink
Quantum Computational Science Group Leader, Oak Ridge National Laboratory

Date: Friday February 4, 12:00pm-12:50pm

Location: Zoom (Meeting ID: 9351 191 9963) https://rit.zoom.us/j/93511919963

Abstract:  Quantum computing is a radically new computing paradigm that leverages the strange rules of quantum mechanics to efficiently perform some computational tasks that would otherwise be infeasible. Owing to its great potential and the recent availability of small prototype devices, quantum computing has become a very popular research field. However, it should be noted that many difficult challenges remain. One such challenge is verifying the outputs of quantum computers, which for the foreseeable future will remain prone to errors. This task is analogous to verifying a probability distribution over an exponentially large set of events, which generally requires exponentially many observations.

I will present a novel method for verifying complex quantum states produced by quantum computers. The method requires only the ability to repeatedly prepare the state to be verified, the ability to perform a few simple quantum operations on the state, and the ability to calculate selected coefficients of the desired state. In contrast to existing verification methods, my method is experimentally efficient for anti-sparse quantum states, which importantly includes many classes of states that are believed to be useful due to their difficulty of being simulated on digital computers. Notably, the proposed method is exponentially more efficient than any non-quantum method, and thus constitutes an example of strong quantum advantage. After describing the method and how it works, I will present the results of numerical simulations that demonstrate its effectiveness for several representative classes of quantum states.

Speaker Biography: Dr. Ryan Bennink leads the Quantum Computational Science Group at Oak Ridge National Laboratory. For the past decade his research interests have revolved around modeling and simulation of quantum computation and developing new quantum computational methods. Prior to that, Dr. Bennink developed state-of-the-art entangled photon sources for quantum information science applications. Dr. Bennink has a Ph.D in optics from the University of Rochester and undergraduate degrees in physics and mathematics. He studied abroad as a Marshall Scholar, was a Sproull Fellow at the University of Rochester, and joined ORNL as a Wigner Fellow in 2004.