Abstract
By investigating information flow between a general parity-time (-)symmetric non-Hermitian system and an environment, we find that the complete information retrieval from the environment can be achieved in the -unbroken phase, whereas no information can be retrieved in the -broken phase. The -transition point thus marks the reversible-irreversible criticality of information flow, around which many physical quantities such as the recurrence time and the distinguishability between quantum states exhibit power-law behavior. Moreover, by embedding a -symmetric system into a larger Hilbert space so that the entire system obeys unitary dynamics, we reveal that behind the information retrieval lies a hidden entangled partner protected by symmetry. Possible experimental situations are also discussed.
- Received 7 June 2017
DOI:https://doi.org/10.1103/PhysRevLett.119.190401
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