Energy absorption by rapidly driven chaotic systems

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• Christopher Jarzynski, University of Maryland
• Tuesday 09 February 2021, 13:00-14:00
• via zoom, meeting ID 940-1803-7756.

If you have a question about this talk, please contact Patrick Pietzonka.

Zoom link: https://maths-cam-ac-uk.zoom.us/j/94018037756

Quantum 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 stabilize these non-equilibrium states against unwanted heating (absorption of energy) from the periodic drive. Prethermalization, in particular, occurs when a rapidly driven system relaxes quickly to an equilibrium-like “prethermal” state, in which it remains for a very long time – often exponential in the driving frequency – before ultimately absorbing energy from the drive. Insight into this phenomenon can be gained by studying the general problem of a classical, chaotic system under periodic driving at frequency ω≫1 (in appropriate units). I will argue that the system’s energy evolves diffusively, and I will present a Fokker-Planck equation for the statistical evolution of the system’s energy. This equation reveals that the system initially absorbs energy extremely slowly, at a rate that generically scales like e^(-ω), in agreement with prethermalization. For many-body systems, these results can be restated in terms of the system’s temperature, which remains at a near-constant value during the long prethermal era, before increasing indefinitely thereafter. Finally, I will combine semiclassical approximations with Fermi’s Golden Rule to argue that the same Fokker-Planck equation can be derived for rapidly driven quantum systems.

This talk is part of the DAMTP Statistical Physics and Soft Matter Seminar series.

This talk is included in these lists:

• All CMS events
• DAMTP Statistical Physics and Soft Matter Seminar
• Soft Matter
• bld31
• via zoom, meeting ID 940-1803-7756

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