Coherent backaction between spins and an electronic bath : non-Markovian dynamics and low-temperature quantum thermodynamic electron cooling
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We provide a versatile analytical framework for calculating the dynamics of a spin system in contact with a fermionic bath beyond the Markov approximation. The approach is based on a second-order expansion of the Nakajima-Zwanzig master equation but systematically includes all quantum coherent memory effects leading to non-Markovian dynamics. Our results describe, for the free induction decay, the full time range from the non-Markovian dynamics at short times, to the well-known exponential thermal decay at long times. We provide full analytic results for the entire time range using a bath of itinerant electrons as an archetype for universal quantum fluctuations. Furthermore, we propose a quantum thermodynamic scheme to employ the temperature insensitivity of the non-Markovian decay to transport heat out of the electron system and thus, by repeated reinitialization of a cluster of spins, to efficiently cool the electrons at very low temperatures.
Matern , S , Loss , D , Klinovaja , J & Braunecker , B 2019 , ' Coherent backaction between spins and an electronic bath : non-Markovian dynamics and low-temperature quantum thermodynamic electron cooling ' , Physical Review. B, Condensed matter and materials physics , vol. 100 , no. 13 , 134308 . https://doi.org/10.1103/PhysRevB.100.134308
Physical Review. B, Condensed matter and materials physics
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DescriptionS.M. acknowledges the support by the EPSRC under Grant No. EP/L015110/1. D.L. and J.K. acknowledge the support by the Swiss National Science Foundation and NCCR QSIT.
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