2017/08/31 by Junjie Liu, Chang-Yu Hsieh, Jianshu Cao +1
Materials Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Context (archaeology) #Coupling (piping) #Heat current #Noise (video) #Quantum #Quantum and electron transport phenomena #Quantum noise #Scaling #Thermal properties of materials #White noise #cond-mat.mes-hall #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1063/1.5025367
published as J. Chem. Phys. 148, 234104 (2018) · 10 pages, 7 figures, comments are welcome
openalex created_date 2017/08/31 · arxiv created 2017/11/19 · openalex publication_date 2018/06/20 · arxiv updated 2018/06/22 · openalex updated_date 2026/08/05
To investigate frequency-dependent current noise (FDCN) in open quantum systems at steady states, we present a theory which combines Markovian quantum master equations with a finite time full counting statistics. Our formulation of the FDCN generalizes previous zero-frequency expressions and can be viewed as an application of MacDonald's formula for electron transport to heat transfer. As a demonstration, we consider the paradigmatic example of quantum heat transfer in the context of a non-equilibrium spin-boson model. We adopt a recently developed polaron-transformed Redfield equation which allows us to accurately investigate heat transfer with arbitrary system-reservoir coupling strength, arbitrary values of spin bias, and temperature differences. We observe a turn-over of FDCN in the intermediate coupling regimes, similar to the zero-frequency case. We find that the FDCN with varying coupling strengths or bias displays a universal Lorentzian-shape scaling form in the weak coupling regime, and a white noise spectrum emerges with zero bias in the strong coupling regime due to distinctive spin dynamics. We also find that the bias can suppress the FDCN in the strong coupling regime, in contrast to its zero-frequency counterpart which is insensitive to bias changes. Furthermore, we utilize the Saito-Utsumi relation as a benchmark to validate our theory and study the impact of temperature differences at finite frequencies. Together, our results provide detailed dissections of the finite time fluctuation of heat current in open quantum systems.