CMSA Quantum Matter in Mathematics and Physics: Maximal quantum chaos of the critical Fermi surface


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January 28, 2022 2:30 pm - 4:00 pm
via Zoom Video Conferencing

Maria Tikhanovskaya - Harvard

In this talk, I will describe many-body quantum chaos in a recently proposed large-N theory for critical Fermi surfaces in two spatial dimensions, by computing out-of-time-order correlation functions. I will use the ladder identity proposed by Gu and Kitaev, and show that the chaos Lyapunov exponent in this system takes on the maximum possible value of 2πkBT/ℏ, where T is the absolute temperature. In addition, by varying the dynamic critical exponent, I will show that the maximal chaos persists only in the regime where quasiparticles are absent. When quasiparticles are present, the Lyapunov exponent scales with the temperature as ~ T^a, where a < 1, which is parametrically smaller than the maximal rate.
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