Quantum physics meeting: Juliette Monsel "Energy transport and refrigeration with driven quantum dots"

NanoLund Quantum Physics meeting with guest speaker  Juliette Monsel from Chalmers, who will be presenting on the topic of:

Energy transport and refrigeration with driven quantum dots

Friday 31 March 9:00 - 10:00 in k-space at FTF, Fysicum

Abstract:

Thermal transport in quantum dots has been extensively studied in the context of steady-state heat engines, e.g. [1]. However, quantum dots are also relevant for cyclic thermal machines as they can be time-dependently driven, e.g., to pump charge. Understanding the characteristics of energy transport in periodically driven quantum dots is therefore important. I will present the simple case of a driven single-level quantum dot weakly coupled to two electronic contacts. The dot has an onsite interaction, which can be either repulsive, like the typical Coulomb interaction, or attractive, as realized experimentally, e.g. in Refs. [2-4].

In the first part, I will focus on the case of slow driving, allowing for a geometric approach that we combined with a fermionic duality for the evolution operator of the master equation [5], which provides compact and insightful analytic expressions [6]. I will show the concrete effects of strong many-body interaction and the impact of the interaction sign on energy transport. Then, I will explain how to use this device as a heat pump or refrigerator and highlight the crucial role of the interaction sign in the performances of these thermal machines. In the second part, I will present a more traditional 4-stroke thermodynamic cycle to operate the dot as a refrigerator and show the impact of the onsite interaction on the thermal machine performances, from strongly attractive to strongly repulsive, through weak interaction strength [7].

[1] M. Josefsson, et al. Nat. Nanotechnol. 13, 920 (2018)

[2] A. Hamo, et al.. Nature 535, 395 (2016)

[3] G. Cheng, et al. Phys. Rev. X 6, 041042 (2016)

[4] G. E. D. K. Prawiroatmodjo, et al. Nat. Commun. 8, 1 (2017)

[5] J. Schulenborg, et al. Phys. Rev. B 93, 081411 (2016)

[6] J. Monsel, J. Schulenborg, T. Baquet, J. Splettstoesser. Phys. Rev. B, 106, 035405 (2022)

[7] J. Monsel, J. Schulenborg, J. Splettstoesser. Eur. Phys. J. Spec. Top (in prep.)