Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 42: Other Transport Topics
TT 42.11: Talk
Wednesday, March 11, 2026, 12:15–12:30, HSZ/0105
Thermodynamic and kinetic uncertainty relations in topological surface states — •Phillip Mercebach1, Pablo Burset1, and Sun-Yong Hwang2 — 1Department of Theoretical Condensed Matter Physics and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain — 2Theoretische Physik, Universitat Duisburg-Essen and CENIDE, D-47048 Duisburg, Germany
Strong fluctuations in nanoscale devices can hinder output precision, while the unavoidable entropy production is detrimental to performance. Device operation can be optimized to achieve a strong output signal while minimizing noise, entropy, and frenesy. However, there are fundamental constraints between the output and these drawbacks: the thermodynamic uncertainty relation (TUR) quantifies the trade-off between signal-to-noise ratio (SNR) and entropy, while the kinetic uncertainty relation (KUR) describes the trade-off between SNR and frenesy. Both relations are especially interesting as quantum coherent processes can yield output precisions surpassing classical limits. Here, we study TUR and KUR in a ballistic junction comprised of a 3D topological insulator (3DTI) in proximity to a ferromagnet. The 3DTI surface states, in combination with the ferromagnet, enable near-Carnot efficiency, indicating low entropy production [1]. We demonstrate that the SNR in this device becomes very high at optimum temperatures and voltage bias, where the thermal and shot noises are rather suppressed.
[1] P. Mercebach et. al., arXiv:2508.20969
Keywords: Kinetic uncertainty relation; Thermodynamic uncertainty relation; Qunatum Noise; Thermoelectric effects; Topological insulator