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SUMMARY:Energy absorption by rapidly driven chaotic systems - Christopher 
 Jarzynski\, University of Maryland
DTSTART:20210209T130000Z
DTEND:20210209T140000Z
UID:TALK156058@talks.cam.ac.uk
CONTACT:Patrick Pietzonka
DESCRIPTION:Zoom link: https://maths-cam-ac-uk.zoom.us/j/94018037756\n\nQu
 antum and classical systems can be driven into interesting and potentially
  useful non-equilibrium states by the application of time-periodic forcing
 .  Phenomena such as _time-crystallization_ and _prethermalization_ can st
 abilize these non-equilibrium states against unwanted heating (absorption 
 of energy) from the periodic drive.  Prethermalization\, in particular\, o
 ccurs when a rapidly driven system relaxes quickly to an equilibrium-like 
 “prethermal” state\, in which it remains for a very long time – ofte
 n exponential in the driving frequency – before ultimately absorbing ene
 rgy from the drive.  Insight into this phenomenon can be gained by studyin
 g the general problem of a classical\, chaotic system under periodic drivi
 ng at frequency ω≫1 (in appropriate units).  I will argue that the syst
 em’s energy evolves diffusively\, and I will present a Fokker-Planck equ
 ation for the statistical evolution of the system’s energy.  This equati
 on reveals that the system initially absorbs energy extremely slowly\, at 
 a rate that generically scales like e^(-ω)\, in agreement with prethermal
 ization.  For many-body systems\, these results can be restated in terms o
 f the system’s temperature\, which remains at a near-constant value duri
 ng the long prethermal era\, before increasing indefinitely thereafter.  F
 inally\, I will combine semiclassical approximations with Fermi’s Golden
  Rule to argue that the same Fokker-Planck equation can be derived for rap
 idly driven quantum systems.\n
LOCATION:via zoom\, meeting ID 940-1803-7756
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