Spontaneous Strong Symmetry Breaking in Open Systems: Purification Perspective

• URL: http://arxiv.org/abs/2405.02402v1
• Date: Fri, 3 May 2024 18:00:04 GMT
• Title: Spontaneous Strong Symmetry Breaking in Open Systems: Purification Perspective
• Authors: Pablo Sala, Sarang Gopalakrishnan, Masaki Oshikawa, Yizhi You,
• Abstract summary: We analyze the spontaneous strong-to-weak symmetry breaking in mixed states triggered by local quantum channels. We map this decoherence process to unitary operations in the purified state within an extended Hilbert space. This purification perspective is further extended to explore intrinsic mixed-state topological order and decoherent symmetry-protected topological phases.
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• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We explore the landscape of the decoherence effect in mixed-state ensembles from a purification perspective. We analyze the spontaneous strong-to-weak symmetry breaking (SSSB) in mixed states triggered by local quantum channels by mapping this decoherence process to unitary operations in the purified state within an extended Hilbert space. Our key finding is that mixed-state long-range order and SSSB can be mapped into symmetry-protected topological (SPT) order in the purified state. Notably, the measurement-induced long-range order in the purified SPT state mirrors the long-range order in the mixed state due to SSSB, characterized by the Renyi-2 correlator. We establish a correspondence between fidelity correlators in the mixed state, which serve as a measure of SSSB, and strange correlators in the purification, which signify the SPT order. This purification perspective is further extended to explore intrinsic mixed-state topological order and decoherent symmetry-protected topological phases.

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