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arXiv · 1708.00871

Spread of entanglement in a Sachdev-Ye-Kitaev chain

Yingfei Gu·Andrew Lucas·Xiao-Liang Qi
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Abstract

We study the spread of Rényi entropy between two halves of a Sachdev-Ye-Kitaev (SYK) chain of Majorana fermions, prepared in a thermofield double (TFD) state. The SYK chain model is a model of chaotic many-body systems, which describes a one-dimensional lattice of Majorana fermions, with spatially local random quartic interaction. We find that for integer Rényi index $n>1$, the Rényi entanglement entropy saturates at a parametrically smaller value than expected. This implies that the TFD state of the SYK chain does not rapidly thermalize, despite being maximally chaotic: instead, it rapidly approaches a prethermal state. We compare our results to the signatures of thermalization observed in other quenches in the SYK model, and to intuition from nearly-$\mathrm{AdS}_2$ gravity.

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Yingfei Gu, Andrew Lucas, Xiao-Liang Qi. 2017-08-02. Spread of entanglement in a Sachdev-Ye-Kitaev chain. https://doi.org/10.1007/jhep09(2017)120

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