Heat flux and information backflow in cold environments

Abstract

We examine non-Markovian effects in an open quantum system from the point of view of information flow. To this end, we consider the spin-boson model with a cold reservoir, accounting for the exact timedependent correlations between the system and the bath to study the exchange of information and heat. We use an information-theoretic measure of the relevant memory effects and demonstrate that the information backflow from the reservoir to the system does not necessarily correlate with the backflow of heat. We also examine the influence of temperature and coupling strength on the loss and gain of information between the system and the bath. Finally, we discuss how additional driving changes the backflow of information, giving rise to potential applications in reservoir engineering.

Quantifying non-Markovianity due to driving and a finite-size environment in an open quantum system

“…Contrary to other systems in which non-Markovianity has been investigated [6,20,22], the trace distance rate starts from negative values. In those works, the time-dependent transition rates are continuous at time t = 0 and start from 0.…”

“…However, the dynamics can become non-Markovian even in the weak coupling regime if the environment is either very cold [20] or finite [21,[32][33][34]. This is especially important in stochastic thermodynamics of open quantum systems, where non-Markovianity plays a crucial role in the detection of heat and work.…”

“…For such systems a detailed understanding of the memory effects is desirable. The study of non-Markovianity in open quantum systems has become a subject of broad interest in recent years due to the rapid development in quantum information [5,6] and in quantum thermodynamics [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. There is a great variety of nonMarkovianity measures for open quantum systems proposed in the literature [22][23][24][25][26][27][28][29][30], which are not identical.…”

Witness for initial correlations among environments

“…can be regarded as a quantifier for the information exchange between an open system and its environment [18]. In Eq.…”

Energy backflow in strongly coupled non-Markovian continuous-variable systems

“…In recent years, much work has been devoted to understand energy flow and transport properties in the context of open quantum systems [1][2][3][4][5][6]. These questions naturally arise since all realistic quantum systems are open and interact with their environments, which in many cases can be modelled as generic heat baths consisting of bosonic modes.…”