Quantum Mpemba effect of Z2 symmetry restoration in the Dicke model

arXiv:2611.00902v1 Announce Type: new Abstract: We study a symmetry-restoration quantum Mpemba effect in the dissipative Dicke model as an example of a weakly $\mathbb Z_2$-symmetric open quantum system, where the full Liouvillian is parity covariant although individual quantum jumps connect the two Hilbert-space parity sectors. Using the entanglement-asymmetry (EA) diagnostic to monitor parity restoration, we compare coherent-product and cat-product initial states. Coherent-product states show conventional relaxation, with larger initial asymmetry decaying more slowly and no Mpemba crossing observed. Cat-product states, by contrast, can reverse this hierarchy over a finite region of initial-state space.