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Sumilan Banerjee (Indian Institute of Science, Bengaluru)
Date & Time
Tue, 08 June 2021, 15:00 to 16:30
Online Seminar

Chaotic quantum systems with Lyapunov exponent $\lambda_L$ obey a remarkable upper bound $\lambda_L\leq 2\pi k_BT/\hbar$ at temperature $T$, implying a divergence of the bound in the classical limit $\hbar\rightarrow 0$. Following this trend, does a quantum system necessarily become ‘more chaotic' when quantum fluctuations are reduced? I will explore this question by computing $\lambda_L(\hbar ,T )$ in the quantum spherical p-spin glass model, where $\hbar$ can be continuously varied. I will show that the approach to the classical limit could be non-trivial, with non-monotonic dependence of $\lambda_L$ on $\hbar$ close to the dynamical glass transition temperature $T_d$. The results in the classical limit ( $\hbar\rightarrow 0$ ) naturally describe chaos in super-cooled liquid in structural glasses. I will also discuss chaos in the replica symmetry breaking spin glass phase. If time permits, I will briefly discuss many-body chaos across Kosterlitz-Thouless and Ising transitions in the classical limit of two-dimensional XXZ spin model.

Zoom link:
Meeting ID:  914 5847 1087
Passcode:  654084