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arXiv · 1907.01569

Structure of Quantum Entanglement at a Finite Temperature Critical Point

Tsung-Cheng Lu·Tarun Grover
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Abstract

We propose a scheme to characterize long-range quantum entanglement close to a finite temperature critical point using tripartite entanglement negativity. As an application, we study a model with mean-field Ising critical exponents and find that the tripartite negativity does not exhibit any singularity in the thermodynamic limit across the transition. This indicates that the long-distance critical fluctuations are completely classical, allowing one to define a `quantum correlation length' that remains finite at the transition despite a divergent physical correlation length. Motivated by our model, we also study mixed state entanglement in tight-binding models of bosons with $U(1)$ and time-reversal symmetry. By employing Glauber-Sudarshan `P-representation', we find a surprising result that such states have zero entanglement.

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Tsung-Cheng Lu, Tarun Grover. 2019-07-02. Structure of Quantum Entanglement at a Finite Temperature Critical Point. https://doi.org/10.1103/physrevresearch.2.043345

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