Fragility of time-reversal symmetry protected topological phases

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• Max McGinley (Department of Physics, University of Cambridge)
• Friday 28 August 2020, 09:40-10:00
• Online - Zoom.

If you have a question about this talk, please contact Joseph Nelson.

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 that 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 utilizing topological systems for quantum technologies.

References:

M. McGinley and N. R. Cooper, Nature Physics (2020).

This talk will be held online using Zoom. Please register your email address here to receive Zoom links via email.

Workshop website: https://www.mtg.msm.cam.ac.uk/events/msm-aimr-joint-online-workshop-2020

This talk is part of the MSM-AIMR Joint Online Workshop 2020 series.

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• MSM-AIMR Joint Online Workshop 2020
• Online - Zoom

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