Measuring topological entanglement entropy using Maxwell relations

Sarath Sankar; Eran Sela; Cheolhee Han

doi:10.1103/physrevlett.131.016601

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arXiv · 2212.09856

Measuring topological entanglement entropy using Maxwell relations

Sarath Sankar·Eran Sela·Cheolhee Han

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Abstract

Topological entanglement entropy (TEE) is a key diagnostic of topological order, allowing to detect the presence of Abelian or non-Abelian anyons. However, there are currently no protocols to measure TEE in condensed matter systems. Here, we propose a scheme to measure the TEE, based on a nontrivial connection with the thermodynamic entropy change occurring in a quantum point contact (QPC) as it pinches off the topological liquid into two. We show how this entropy change can be extracted using Maxwell relations from charge detection of a nearby quantum dot. We demonstrate this explicitly for the Abelian Laughlin states, using an exact solution of the sine-Gordon model describing the universal crossover in the QPC. Our approach might open a new thermodynamic detection scheme of topological states also with non-Abelian statistics.

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Sarath Sankar, Eran Sela, Cheolhee Han. 2022-12-19. Measuring topological entanglement entropy using Maxwell relations. https://doi.org/10.1103/physrevlett.131.016601

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