Thermodynamics of a qubit undergoing dephasing

7th Young Researcher Meeting

Marcantoni, S.^1,2

Dipartimento di Fisica, Universita di Trieste, Trieste

I-34151, Italy^1

Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste

I-34151, Italy^2

关键词: Arbitrary couplings;    Entropy production;    External environments;    Lindblad master equation;    Master equations;    Quantum harmonic oscillators;    Second Law of Thermodynamics;    Weak-coupling limits;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/841/1/012019/pdf
DOI  :  10.1088/1742-6596/841/1/012019

来源: IOP

【 摘 要 】

The thermodynamics of a qubit undergoing dephasing due to the coupling with the external environment is discussed. First of all, we assume the dynamics of the system to be described by a master equation in Lindblad form. In this framework, we review a standard formulation of the first and second law of thermodynamics that has been known in literature for a long time. After that, we explicitly model the environment with a set of quantum harmonic oscillators choosing the interaction such that the global dynamics of system and bath is analytically solvable and the Lindblad master equation is recovered in the weak-coupling limit. In this generalized setting, we can show that the correlations between system and bath play a fundamental role in the heat exchange. Moreover, the internal entropy production of the qubit is proven to be positive for arbitrary coupling strength.