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arXiv · 2510.25519

Dynamics of entanglement fluctuations and quantum Mpemba effect in the $ν=1$ QSSEP model

Angelo Russotto·Filiberto Ares·Pasquale Calabrese·Vincenzo Alba
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Abstract

We study the out-of-equilibrium dynamics of entanglement fluctuations in the $ν=1$ Quantum Symmetric Simple Exclusion Process, a free-fermion chain with hopping amplitudes that are stochastic in time but homogeneous in space. Previous work showed that the average entanglement growth after a quantum quench can be explained in terms of pairs of entangled quasiparticles performing random walks, leading to diffusive entanglement spreading. By incorporating the noise-induced statistical correlations between the quasiparticles, we extend this description to the full-time probability distribution of the entanglement entropy. Our generalized quasiparticle picture allows us to compute the average time evolution of a generic function of the reduced density matrix of a subsystem. We also apply our result to the entanglement asymmetry. This allows us to investigate the restoration of particle-number symmetry in the dynamics from initial states with no well-defined particle number. Regarding the possible existence of the quantum Mpemba effect, our analysis indicates that its occurrence is an extremely fine-tuned phenomenon, requiring very specific conditions and therefore being rather difficult to observe in practice.

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Angelo Russotto, Filiberto Ares, Pasquale Calabrese, Vincenzo Alba. 2026-05-08. Dynamics of entanglement fluctuations and quantum Mpemba effect in the $ν=1$ QSSEP model. https://doi.org/10.1088/1742-5468%2Fae4bb9

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