Monitored quantum systems and entanglement transitions

Abstract:

Quantum measurements do not only reveal the state of a quantum system; when applied continuously or repeatedly, they can qualitatively change its many-body dynamics, suppressing thermalisation via the quantum Zeno effect. In this talk, I will discuss how the competition between unitary evolution and monitoring gives rise to a new class of nonequilibrium critical phenomena: measurement-induced entanglement transitions, separating phases with extensive (volume-law) and subextensive (area-law) entanglement scaling. Over the past several years, this phenomenon has opened a broad research direction at the interface of quantum statistical mechanics, quantum information, and open quantum systems.

We will see how monitored systems can be understood intuitively through several pictures: entanglement growth, purification dynamics, and mappings to stat-mech models. Building on this, I will discuss results on the effects of interactions, disorder, symmetries, and dimensionality, highlighting how one can alter the measurement-induced critical behavior and the dynamical phases. I will conclude by describing how controlled monitoring can be harnessed for quantum information processing (state preparation, error mitigation), pointing to future applications in quantum computing architectures.

This special seminar will take place on 25 March, 11AM-12AM, in the ground floor Lecture Hall in Al. Lotników, available on Zoom under the following link:

https://us06web.zoom.us/j/86976039901?pwd=Nxw4V42bAvQeF5ao88rbQBLTSHBa5n.1

ID: 869 7603 9901
Passcode: 148188