Ritu Nehra

(University of the Negev, Israel)

Abstract:

The dynamics of entanglement under measurement in many-body quantum systems is a topic under intensive study recently. The generic unitary dynamics give rise to the ther- malization in the system due to a highly entangled state, whereas continuous monitoring of these states tends to destroy all the entanglements. The two competing dynamics are responsible for the exciting phase transitions in the quantum systems, which are studied with the help of the entanglement entropy scaling [1]. The experimental probing of these measurements is independent of environmental feedback, which restricts its applicability to a few open systems. In order to capture a large class of environments, the measur- ing device is modeled as a continuous Gaussian probe in recent work [2], which modifies the detector state and uses it as feedback to the systems. I will discuss the role of the feedback control measurements in the context of topological phase transitions of the free Fermionic chains [3]. I will try to address questions like how the special measurement operations and environmental feedback influence the topology in such systems and how the probabilities [4] and relative strengths [2] of two competing measurements give rise to various phase transitions exhibiting different universality. 

Reference:
[1] Brian Skinner, Jonathan Ruhman and Adam Nahum, Measurement-Induced Phase Transi- tions in the Dynamics of Entanglement, PhysRevX.9.031009, 2019.

[2] Graham Kells, Dganit Meidan and Alessandro Romito, Topological transitions in weakly monitored free Fermions, SciPostPhys.14.3.031, 2023.

[3] M. Szyniszewski, A. Romito, and H. Schomerus, Entanglement transition from variable- strength weak measurements, Phys. Rev. B 100, 064204, 2019.

[4] Ali Lavasani, Yahya Alavirad and Maissam Barkeshli, Measurement-induced topological en- tanglement transitions in symmetric random quantum circuits, Nature Physics 17, 342–347, 2021.