Arthur Parzygnat (MIT): A temporal analogue of quantum states for sequential measurements and time-reversal symmetry

Date and Time

November 26, 2024
04:30PM - 05:30PM EST

Location

Jefferson 356 and Zoom

 

Zoom link: https://harvard.zoom.us/j/779283357?pwd=MitXVm1pYUlJVzZqT3lwV2pCT1ZUQT09

Passcode: 657361

Speaker: Arthur Parzygnat

Title: A temporal analogue of quantum states for sequential measurements and time-reversal symmetry

Abstract: If a quantum state distributed over regions of space provides the expectation values of observables on those regions, what object provides the expectation values of observables measured sequentially in time? We will first provide a rigorous definition of such quantum "states over time". Using such a definition will naturally lead us to an extension of Bayes' rule from classical probability to quantum systems. Such a quantum Bayes' rule provides concrete predictions for the construction of processes that admit time-reversal symmetric expectation values of measurements. We will analyze the concrete example of an amplitude-damping channel on qubits.