Entropy measurement of a strongly correlated quantum dot

ORAL

Abstract

The spin 1/2 entropy of electrons trapped in a quantum dot has previously been measured with great accuracy, but the protocol used for that measurement is valid only within a restrictive set of conditions. Here, we present a novel entropy measurement protocol that is universal for arbitrary mesoscopic circuits and the application of this new approach to measure the entropy of a quantum dot hybridized with a reservoir. The experimental results are compared to numerical renormalization group calculations and demonstrate a clear modification to the entropy due to Kondo correlations. For the largest couplings investigated in this work, NRG predicts a suppression of spin entropy due to the formation of a Kondo singlet. This suppression is not observed in the experiment, perhaps indicating dephasing of the Kondo singlet by the charge sensor.

*This project has received funding from European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme under grant agreement No 951541. Y. Meir acknowledges discussions with A. Georges and support by the Israel Science Foundation (grant 3523/2020). Experiments at UBC were undertaken with support from the Stewart Blusson Quantum Matter Institute, the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, the Canadian Institute for Advanced Research, and the Canada First Research Excellence Fund, Quantum Materials and Future Technologies Program.

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Publication: Planned Papers:
Entropy measurement of a strongly correlated quantum dot
A robust protocol for entropy measurement in mesoscopic circuits

Presenters

  • Tim J Child

    • University of British Columbia

Authors

  • Tim J Child

    • University of British Columbia

  • Owen I Sheekey

    • University of British Columbia

  • Silvia Lüscher

    • University of British Columbia

  • Saeed Fallahi

    • Purdue University

  • Geoffrey C Gardner

    • Purdue University
    • Purdue University, Microsoft Quantum Materials Lab-Purdue, West Lafayette, Indiana 47907, USA)
    • Microsoft Quantum Materials Lab-Purdue

  • Michael J Manfra

    • Department of Physics and Astronomy, Birck Nanotechnology Center, and Microsoft Quantum Lab Purdue, Purdue University
    • Purdue University
    • Purdue University, West Lafayette, Indiana 47907, USA

  • Yaakov Kleeorin

    • Center for the Physics of Evolving Systems, University of Chicago
    • University of Chicago

  • Yigal Meir

    • Ben-Gurion University of the Negev

  • Joshua Folk

    • University of British Columbia