Periodically refreshed baths to simulate open quantum many-body dynamics

Periodically refreshed quantum thermal machines

“…We have found that the PReB process can be realized with a finite number of copies of each bath, relying on their self-rethermalization when disconnected from the system. With increase in τ , the PReB process converges, both dynamically and thermodynamically, to the continuous-time autonomous process, where the baths are kept connected without any refreshing [5]. We have found that, if the bath spectral functions approach a Dirac-delta function, the PReB process can reduce to a standard collisional model based on repeated interactions with single-site environments [10,11].…”

“…It has been proven [5] that if there is a unique steady state of the continuous-time dynamics generated by Λ(t), the state of the system obtained by the PReB process will converge to that obtained by the continuous-time dynamics for increasing τ , ρPReB (nτ ) → ρ(nτ ), with increase in τ . (5) This observation was used to develop a numerically efficient way to obtain the full non-Markovian dynamics of interacting quantum many-body systems [5]. Here, by decreasing τ below the system time-scales we will enter a regime where the system does not have enough time to react to the presence of the baths before the baths are refreshed.…”

“…(3) means Λ(τ ) describes the time evolution in the presence of macroscopic baths. Interestingly, for the canonical description of thermal baths in terms of an infinite number of bosonic or fermionic modes, one can get the same Λ(τ ) considering the baths to be particular finite-sized chains of size L B ∝ τ [5]. The canonical model for thermal baths is given as follows,…”

“…We find that, if the bath spectral functions approach a Dirac-delta function, the PReB process reduces to standard collisional models with single-site environments. Meanwhile, it has been shown that, with increase in τ the state obtained from the PReB process converges to that from the continuous-time autonomous process [5]. Thus, the unique QTMs at the NESS of the PReB process can interpolate between QTMs based on standard collisional models and autonomous QTMs realized at the NESS in presence of multiple macroscopic baths (for example, absorption refrigerators [18] and thermoelectric devices [19]).…”

Collisional open quantum dynamics with a generally correlated environment: Exact solvability in tensor networks

“…Another approach is based on a past-future independence for environment degrees of freedom interacting with the system [13] -the assumption that is naturally fulfilled in a conventional collision model (also known as the repeated interactions model) with uncorrelated environment particles [14][15][16][17][18]. The latter approach has received increasing attention in the analysis of quantum nonequilibrium steady states [19][20][21], bipartite and multipartite entanglement generation [21][22][23], quantum thermodynamical analysis of micromasers [24], quantum thermometry [25], and simulation of open quantum many-body dynamics [26,27]; see the recent review papers on collision models [28,29].…”