Thermal power of heat flow through a qubit

Abstract

In this paper we consider thermal power of a heat flow through a qubit between two baths. The baths are modeled as set of harmonic oscillators initially at equilibrium, at two temperatures. Heat is defined as the change of energy of the cold bath, and thermal power is defined as expected heat per unit time, in the long-time limit. The qubit and the baths interact as in the spin-boson model, i.e. through qubit operator σz. We compute thermal power in an approximation analogous to "noninteracting blip" (NIBA) and express it in the polaron picture as products of correlation functions of the two baths, and a time derivative of a correlation function of the cold bath. In the limit of weak interaction we recover known results in terms of a sum of correlation functions of the two baths, a correlation functions of the cold bath only, and the energy split.

Photonic heat transport across a Josephson junction

“…The same expression has been recently derived for a two level system in Ref. 50 . Interestingly, the correction (86) can be transformed to the Landauer form (2) with the aid of the detailed balance relations…”

Out-of-time-ordered correlation functions in open systems: A Feynman-Vernon influence functional approach

“…The main used tool is the Feynman-Vernon influence functional [30], which allows to capture an influence of the environment on the studied system. This approach proved useful both from practical [31][32][33] as well as fundamental point of view [34][35][36], and still provides insights into problems encountered in fields such as open systems [37], quantum thermodynamics [38][39][40][41][42][43][44] or quantum computing [45]. As we show here it encapsulates decoherence of OTOCs in therms of the microscopic parameters of the considered model, allows to gain better insight into differences between the two considered backward time evolution schemes as well as has useful applications e.g.…”

Large deviations and fluctuation theorem for the quantum heat current in the spin-boson model

“…In Refs. [32][33][34] the authors start from the generating function of the heat current to study its first moment. Numerical studies include simulations based on hierarchical equations of motion [35][36][37][38][39][40] the quasiadiabatic propagator path integral (QuAPI) [41,42], the iterative full counting statistics path integral [43], the multiconfiguration time-dependent Hartree (MCTDH) approach [44], the stochastic Liouvillian algorithm [45], and other Monte Carlo approaches [46].…”

“…Following Ref. [34], this generating function can be written explicitly as Feynman-Vernon-type path integral. Relying on a modified version of the NIBA, an expression for the first moment of the generating function, i.e., the average heat current, was obtained by directly applying the NIBA in Ref.…”