SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 38: Nonequilibrium Quantum Many-Body Systems II (joint session TT/DY)

TT 38.7: Talk

Wednesday, March 29, 2023, 16:45–17:00, HSZ 204

Charge, spin, and heat shot noises in the absence of average currents — •Ludovico Tesser, Matteo Acciai, Christian Spånslätt, Juliette Monsel, and Janine Splettstoesser — Chalmers University of Technology, Gothenburg, Sweden

Shot noise in electronic conductors occurs when the system is brought out of equilibrium, e.g., by a stationary bias. However, nonequilibrium does not imply that an average current flows. Indeed, the situation where selected currents are suppressed is of interest in fields like thermoelectrics and spintronics, raising the question of how the related noises behave.

I will present results on zero-current charge, spin, and heat noises in two-terminal mesoscopic conductors induced by voltage, spin and temperature biases. The nonequilibrium shot noises can be arbitrarily large, even if the respective average currents vanish. However, as soon as a temperature bias is present, additional equilibrium (thermal-like) noise necessarily occurs. This equilibrium noise sets an upper bound on the zero-current nonequilibrium charge and spin shot noise [1,2]. We have shown that the bound on the charge noise for strictly two-terminal conductors even extends into the finite-frequency regime. By contrast, these bounds can be overcome for heat transport by breaking the spin and electron-hole symmetries, respectively.
[1] J. Eriksson, M. Acciai, L. Tesser, J. Splettstoesser, Phys. Rev. Lett. 127, 136801 (2021)
[2] L. Tesser, M. Acciai, C. Spånslätt, J. Monsel, J. Splettstoesser, arXiv:2210.06051 [cond-mat.mes-hall] (2022)