Starts 10 Jun 2025 11:00
Ends 10 Jun 2025 12:00
Central European Time
CMSP Seminar (Joint ICTP/SISSA Statistical Physics): Understanding bipartite particle number fluctuation and Page curve entanglement entropy in dephased fermionic lattice systems
Luigi Stasi Seminar Room (Leonardo Building) and via Zoom
Bijay Kumar Agarwalla
(Indian Institute of Science Education and Research, Pune)
Abstract:
The universal properties of nonequilibrium dynamics in many-body quantum systems, particularly the relaxation of both local and non-local observables, have attracted significant attention in recent years.
The eigenstate thermalization hypothesis (ETH), for example, successfully predicts the rapid relaxation of local observables. In contrast, the relaxation dynamics of non-local observables extend beyond ETH and their equilibration is described by a few-parameter hydrodynamic model, reflecting the significantly slower relaxation processes involved. Furthermore, advances in experimental techniques have enabled access to different non-local observables. A key non-local observable in quantum systems is the subsystem particle number fluctuation. In this talk, I will focus on a fermionic lattice system subjected to local dephasing at each lattice site and show how the bipartite particle number fluctuations grow and thermalize. We show that the particle number fluctuation dynamics exhibit one-parameter Family-Vicsek scaling, I will then talk about how for such setups, one can understand Page curve entanglement entropy and how different unraveling of the same physical setup can give rise to rich dynamics and system-size dependence for entanglement entropy.
The eigenstate thermalization hypothesis (ETH), for example, successfully predicts the rapid relaxation of local observables. In contrast, the relaxation dynamics of non-local observables extend beyond ETH and their equilibration is described by a few-parameter hydrodynamic model, reflecting the significantly slower relaxation processes involved. Furthermore, advances in experimental techniques have enabled access to different non-local observables. A key non-local observable in quantum systems is the subsystem particle number fluctuation. In this talk, I will focus on a fermionic lattice system subjected to local dephasing at each lattice site and show how the bipartite particle number fluctuations grow and thermalize. We show that the particle number fluctuation dynamics exhibit one-parameter Family-Vicsek scaling, I will then talk about how for such setups, one can understand Page curve entanglement entropy and how different unraveling of the same physical setup can give rise to rich dynamics and system-size dependence for entanglement entropy.
References:
1. Bipartite particle number fluctuations in dephased long-range lattice systems, Lokesh Tater, Subhajit Sarkar, Devendra Singh Bhakuni, and Bijay Kumar Agarwalla [arXiv: 2503.20356]
2. Quantum trajectories and Page-curve entanglement dynamics, Katha Ganguly, Preethi Gopalakrishnan, Atharva Naik, Bijay Kumar Agarwalla, Manas Kulkarni,[arXiv:2501.12110]