Dynamics and thermodynamics of nanoscale devices

Kinetic Uncertainty Relations for Quantum Transport

Didrik Palmqvist, Ludovico Tesser, Janine Splettstoesser

We analyze the precision of currents in a generic multi-terminal quantum-transport setting. Employing scattering theory, we show that the precision of the currents is limited by a function of the particle-current noise that can be interpreted as the activity in the classical limit. We thereby establish a kinetic uncertainty relation for quantum transport. In the full quantum limit, we find precision bounds in which we modify the activity constraints depending on whether the system is fermionic or bosonic. We expect these bounds to be guidelines for any transport process aiming at high precision. 

Accepted for publication in Phys. Rev. Lett.

Out-of-Equilibrium Fluctuation-Dissipation Bounds

Ludovico Tesser, Janine Splettstoesser

We prove a general inequality between the charge current and its fluctuations valid for any non-interacting coherent electronic conductor and for any stationary out-of-equilibrium condition, thereby going beyond established fluctuation-dissipation relations. The developed fluctuation-dissipation bound saturates at large temperature bias and reveals additional insight for heat engines, since it limits the output power by power fluctuations. It is valid when the thermodynamic uncertainty relations break down due to quantum effects and provides stronger constraints close to thermovoltage. 

Phys. Rev. Lett. 132, 186304 (2024)

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