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In recent years many candidate setups have been proposed to support exotic quasi-particles, such as Majorana fermions (MFs), which may be relevant for quantum computing, but whether these particles have been observed experimentally is currently a topic of a vivid debate. Entropy measurements can unambiguously separate these quasi-particles from other, simpler excitations. The entropy of a MFs is, for example, log2\/2 (in units of the Boltzman constant), a fractional value that cannot be attributed to a localized excitation. However, standard entropy measurements applicable to bulk systems cannot be utilized in measuring the additional entropy of a mesoscopic device, which may be due to less than a single electron in the device. In this talk I will describe recent theoretical and experimental progress in performing such measurements, either using thermopower and\/or using the Maxwell relations [1,2]. Particular examples will be single and double quantum dots in the Coulomb blockade regime. Lastly I will show how the formalism has been generalized to deduce the entropy from conductance measurements, and, applying it to a setup where two and three-channel Kondo physics have been observed, yields the fractional entropy of a single MF and a single Fibonacci anyon [3]. Lastly I will discuss the backaction of the measurement and discuss the possibility of measuring entanglement entropy [4].<\/p>\n
[1]\u00a0\u00a0 Direct entropy measurement in a mesoscopic quantum system, N. Hartman, et al., Nature Physics 14, 1083 (2018).
\n[2]\u00a0\u00a0 How to measure the entropy of a mesoscopic system via thermoelectric transport, Y. Kleeorin et al., Nature Comm. 10 , 5801 (2019)
\n[3]\u00a0\u00a0 Fractional Entropy of Multichannel Kondo Systems from Conductance-Charge Relations, C. Han et al., Phys. Rev. Lett. 128, 146803 (2022).
\n[4]\u00a0\u00a0 Realistic protocol to measure entanglement at finite temperatures, C. Han, Y. Meir and E. Sela, Phys. Rev. Lett., in press.<\/p>\n","protected":false},"excerpt":{"rendered":"
Prof. Yigal Meir, Department of Physics, Ben Gurion University, Israel Measuring Entropy of Exotic Particles When: 12:00-13:00 CET, April 17th (Monday), 2023 Where: Seminar Room, ICMM-CSIC, Campus de Cantoblanco, Madrid In recent years many candidate setups have been proposed to support exotic quasi-particles, such as Majorana fermions (MFs), which may be relevant for quantum computing, … Continue reading Yigal Meir (17\/04\/2023)<\/span>