Random Interactions

Measuring topological entanglement entropy using Maxwell relations

by Dr. Sarath Sankar (Tel Aviv University)

Thursday, January 5, 2023 from to (Asia/Kolkata)
at A304 and Zoom : Join Zoom Meeting https://zoom.us/j/92722085614?pwd=Y0x6WFI2NlUzS01WWDRFR2VFM1dYdz09 Meeting ID: 927 2208 5614 Passcode: 559938
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. On the experimental side, there has been some remarkable progress in the last few years in measuring thermodynamic entropy in nano- to meso- scale systems. The scheme that we propose to measure TEE is within the reach of current experimental techniques.