Quantum homogenization and state randomization in semiquantal spin systems

Abstract

We investigate dynamics of semi-quantal spin systems in which quantum bits are attached to classically and possibly stochastically moving classical particles. The interaction between the quantum bits takes place when the respective classical particles get close to each other in space. We find that with Heisenberg XX couplings quantum homogenization takes place after a time long enough, regardless of the details of the underlying classical dynamics. This is accompanied by the development of a stationary bipartite entanglement. If the information on the details of the motion of a stochastic classical system is disregarded, the stationary state of the whole quantum subsystem is found to be a complete mixture in the studied cases, though the transients depend on the properties of the classical motion.

Divisibility of quantum dynamical maps and collision models

“…The latter scheme is equivalent to a scenario, when the quantum system in question is coherently coupled to an auxiliary system interacting with Markovian bath via collisions [51,52]. Collision models adequately describe a particle in semi-quantal spin gases [53,54], a micromaser [55], a two-level system that interacts with spatio-temporal modes passing through it only once [56], and more complex systems with involved interaction graphs [57][58][59] as well as experiments with an engineered environment in nuclear magnetic resonance [12] and in photonic systems [11,60,61]. Collision models were also exploited in the microscopic description of Landauer's principle [62].…”

Dynamical Casimir effect and minimal temperature in quantum thermodynamics

“…Our model can be also interpreted as a collision model [36][37][38][39][40][41][42] of irreversible quantum dynamics. Such kind of models were used in the literature to analyze the process of thermalization of a system in contact with a bath.…”

Thermal Contact: Mischief and Time Scales

“…This scenario constitutes a Collision Model and is commonly used in quantum thermodynamics to model thermalization [7][8][9][10][11]. It seems natural to expect that the system will (or at least can) be driven to the temperature of its environment by some bombardment process.…”

“…A significant amount of work has been done investigating this robustness, characterizing the emergence of thermalization from quantum dynamics [1][2][3][4][5][6]. Indeed, use is often made of Collision Models to model thermalization [7][8][9][10][11] in quantum thermodynamics. Such scenarios consider a quantum system repeatedly interacting with (being bombarded by) the constituents of its environment one at a time.…”