Fast Scrambling at the Boundary

• URL: http://arxiv.org/abs/2407.13617v1
• Date: Thu, 18 Jul 2024 15:55:44 GMT
• Title: Fast Scrambling at the Boundary
• Authors: Ancel Larzul, Anirvan M. Sengupta, Antoine Georges, Marco Schirò,
• Abstract summary: Many-body systems which saturate the quantum bound on chaos are attracting interest across a wide range of fields. We study many-body quantum chaos in a quantum impurity model showing Non-Fermi-Liquid physics. Our results highlights two new features: a non-disordered model which is maximally chaotic due to strong correlations at its boundary and a fractionalization of quantum chaos.
• Score: 3.4284444670464675
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Many-body systems which saturate the quantum bound on chaos are attracting interest across a wide range of fields. Notable examples include the Sachdev-Ye-Kitaev model and its variations, all characterised by some form or randomness and all to all couplings. Here we study many-body quantum chaos in a quantum impurity model showing Non-Fermi-Liquid physics, the overscreened multichannel $SU(N)$ Kondo model. We compute exactly the low-temperature behavior of the out-of time order correlator in the limit of large $N$ and large number of channels $K$, at fixed ratio $\gamma=K/N$. Due to strong correlations at the impurity site the spin fractionalizes in auxiliary fermions and bosons. We show that all the degrees of freedom of our theory acquire a Lyapunov exponent which is linear in temperature as $T\rightarrow 0$, with a prefactor that depends on $\gamma$. Remarkably, for $N=K$ the impurity spin displays maximal chaos, while bosons and fermions only get up to half of the maximal Lyapunov exponent. Our results highlights two new features: a non-disordered model which is maximally chaotic due to strong correlations at its boundary and a fractionalization of quantum chaos.

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