Student Seminar | April 29, 16:30
Entanglement structure and memory loss in monitored many-body systems
In quantum mechanics, measurements differ fundamentally from classical physics: observing a quantum system not only reveals information but also modifies its state. In many-body systems, the interplay between quantum measurements and unitary evolution can give rise to a new class of non-equilibrium critical phenomena, known as measurement-induced phase transitions (MIPTs). Unlike traditional phase transitions, MIPTs lack a local order parameter and are instead characterized by changes in the system's entanglement properties. In this talk, I will first explore the dynamics of bipartite and multipartite entanglement within this framework, focusing on the integrable quantum Ising chain. I will show how multipartite quantum correlations provide deeper insights into MIPTs, revealing features that are not captured by the conventional entanglement entropy. Then, I will consider the PXP spin chain, a many-body scarred system featuring non-ergodic revival dynamics, addressing how measurements affect the preservation of initial-state memory. This model exhibits a dual response to measurements: depending on their timing, they can either suppress or enhance the system's recurrences.
References:
[1] A. Paviglianiti, A. Silva, Phys. Rev. B 108, 184302 (2023)
[2] A. Paviglianiti, A. Silva, arXiv:2503.22618 (2025)
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Contact: Karim Chahine