Speaker: Matteo lppoliti (UT Austin)
Time: 10:00-11:00 a.m., October 12, 2023, GMT+8
Venue: Zoom ID: 963 5796 8034 Password: 125125 (Koushare platform) https: //www.koushare.com/lives/room/650487
Abstract:
The dynamics of quantum many-body systems subject to repeated measurements has recently emerged as a rich subject for non-equilibrium physics. Remarkably, these systems can exhibit“measurement-induced phase transitions”(MIPTs) in the structure of quantum correlations, such as entanglement, as a function of the rate or strength of measurements versus unitary interactions. In this talk I will present an alternative point of view on these phenomena, based not on the structure of correlations in post-measurement states of the quantum system, but rather on the information content of the measurement outcomes themselves. The MIPT maps onto a phase transition in theability of an eavesdropper to learn properties of an unknown state of thesystem by monitoring its dynamics. This learnability phase transition can be quantified within the framework of "classical shadow tomography"--a paradigm for learning many properties of quantumstates from randomized measurements--where it arises as an abruptchange in the number of experimental repetitions required to learnvarious properties. This point of view unifies distinct manifestations of the MIPT under a common denominator, and points to new orderparameters that could be used for its experimental detection.
Reference: Ml,V.Khemani, arXiv:2307.15011
Source: School of Physics