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Paper 1
Hayden-Preskill decoding from noisy Hawking radiation
Ning Bao, Yuta Kikuchi
- Year
- 2020
- Journal
- arXiv preprint
- DOI
- arXiv:2009.13493
- arXiv
- 2009.13493
In the Hayden-Preskill thought experiment, the Hawking radiation emitted before a quantum state is thrown into the black hole is used along with the radiation collected later for the purpose of decoding the quantum state. A natural question is how the recoverability is affected if the stored early radiation is damaged or subject to decoherence, and/or the decoding protocol is imperfectly performed. We study the recoverability in the thought experiment in the presence of decoherence or noise in the storage of early radiation.
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Non-Hermitian spectral flows and Berry-Chern monopoles
Lucien Jezequel, Pierre Delplace
- Year
- 2022
- Journal
- arXiv preprint
- DOI
- arXiv:2209.03876
- arXiv
- 2209.03876
We propose a non-Hermitian generalization of the correspondence between the spectral flow and the topological charges of band crossing points (Berry-Chern monopoles). A class of non-Hermitian Hamiltonians that display a complex-valued spectral flow is built by deforming an Hermitian model while preserving its analytical index. We relate those spectral flows to a generalized Chern number that we show to be equal to that of the Hermitian case, provided a line gap exists. We demonstrate the homotopic invariance of both the non-Hermitian Chern number and the spectral flow index, making explicit their topological nature. In the absence of a line gap, our system still displays a spectral flow whose topology can be captured by exploiting an emergent pseudo-Hermitian symmetry.
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