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SUMMARY:Fragility of time-reversal symmetry protected topological phases -
  Max McGinley (Department of Physics\, University of Cambridge)
DTSTART:20200828T084000Z
DTEND:20200828T090000Z
UID:TALK150628@talks.cam.ac.uk
CONTACT:Joseph Nelson
DESCRIPTION:The second law of thermodynamics points to the existence of an
  ‘arrow of time’\, along which entropy only increases. This arises des
 pite the time-reversal symmetry (TRS) of the microscopic laws of nature. W
 ithin quantum theory\, TRS underpins many interesting phenomena\, most not
 ably topological insulators and the Haldane phase of quantum magnets. Here
 \, we demonstrate that such TRS-protected effects are fundamentally unstab
 le against coupling to an environment. Irrespective of the microscopic sym
 metries\, interactions between a quantum system and its surroundings facil
 itate processes that would be forbidden by TRS in an isolated system. This
  leads not only to entanglement entropy production and the emergence of ma
 croscopic irreversibility\, but also to the demise of TRS-protected phenom
 ena\, including those associated with certain symmetry-protected topologic
 al phases. Our results highlight the enigmatic nature of TRS in quantum me
 chanics and elucidate potential challenges in utilizing topological system
 s for quantum technologies.\n\n_References_:\n\nM. McGinley and N. R. Coop
 er\, "Nature Physics (2020).":https://doi.org/10.1038/s41567-020-0956-z\n\
 n*This talk will be held online using Zoom. Please "register your email ad
 dress here":https://forms.gle/9Rpf2BekocwLpmHD9 to receive Zoom links via 
 email.*\n\n*Workshop website:* https://www.mtg.msm.cam.ac.uk/events/msm-ai
 mr-joint-online-workshop-2020
LOCATION:Online - Zoom
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