Can I read Strong-to-Weak Spontaneous Symmetry Breaking in Mixed Quantum States on EtoBox?

Strong-to-Weak Spontaneous Symmetry Breaking in Mixed Quantum States by Lessa, Leonardo A.; Ma, Ruochen; Zhang, Jian-Hao; Bi, Zhen; Cheng, Meng; Wang, Chong is a scholarly article available to read on EtoBox.

What is Strong-to-Weak Spontaneous Symmetry Breaking in Mixed Quantum States about?

Symmetry in mixed quantum states can manifest in two distinct forms: strong symmetry, where each individual pure state in the quantum ensemble is symmetric with the same charge, and weak symmetry, which applies only to the entire ensemble. This paper explores a novel type of spontaneous symmetry breaking (SSB) where a strong symmetry is broken to a weak one. While the SSB of a weak symmetry is measured by the long-ranged two-point correlation function, the strong-to-weak SSB (SW-SSB) is measured by the fidelity correlator. We prove that SW-SSB is a universal property of mixed-state quantum phases, in the sense that the phenomenon of SW-SSB is robust against symmetric low-depth local quantum channels. We also show that the symmetry breaking is "spontaneous" in the sense that the effect of a local symmetry-breaking measurement cannot be recovered locally. We argue that a thermal state at a nonzero temperature in the canonical ensemble (with fixed symmetry charge) should have spontaneously broken strong symmetry. Additionally, we study non-thermal scenarios where decoherence induces SW-SSB, leading to phase transitions described by classical statistical models with bond randomness. In

Author

Lessa, Leonardo A.; Ma, Ruochen; Zhang, Jian-Hao; Bi, Zhen; Cheng, Meng; Wang, Chong

Published

2024

Language

EN