Fragility of time-reversal symmetry protected topological phases
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Publication Date
2020-12Journal Title
Nature Physics
ISSN
1745-2473
Publisher
Springer Science and Business Media LLC
Volume
16
Issue
12
Pages
1181-1183
Type
Article
This Version
AM
Metadata
Show full item recordCitation
McGinley, M., & Cooper, N. (2020). Fragility of time-reversal symmetry protected topological phases. Nature Physics, 16 (12), 1181-1183. https://doi.org/10.1038/s41567-020-0956-z
Abstract
The second law of thermodynamics points to the existence of an `arrow of time', along which entropy only increases. This arises despite the time-reversal symmetry (TRS) of the microscopic laws of nature. Within quantum theory, TRS underpins many interesting phenomena, most notably topological insulators and the Haldane phase of quantum magnets. Here, we demonstrate that such TRS-protected effects are fundamentally unstable against coupling to an environment. Irrespective of the microscopic symmetries, interactions between a quantum system and its surroundings facilitate processes which would be forbidden by TRS in an isolated system. This leads not only to entanglement entropy production and the emergence of macroscopic irreversibility, but also to the demise of TRS-protected phenomena, including those associated with certain symmetry-protected topological phases. Our results highlight the enigmatic nature of TRS in quantum mechanics, and elucidate potential challenges in utilising topological systems for quantum technologies.
Sponsorship
Simons Foundation
Funder references
Engineering and Physical Sciences Research Council (EP/P009565/1)
Engineering and Physical Sciences Research Council (EP/P034616/1)
Simons Foundation (511029)
Identifiers
External DOI: https://doi.org/10.1038/s41567-020-0956-z
This record's URL: https://www.repository.cam.ac.uk/handle/1810/306000
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