Abstract

An interesting class of open quantum systems is defined by the so-called repeated interaction scheme, where the system interacts sequentially with small and fresh subsystems or units coming from a reservoir. The interaction is unitary and relatively easy to analyze. However, it must be switched on and off and these actions may introduce and/or extract energy, performing work and preventing thermalization when the reservoir is a thermal bath. As a consequence, the repeated interaction scheme cannot be used to model thermostats in quantum thermodynamics. In a series of papers, we have partly overcome this problem by considering collisional reservoirs where the units are quantum particles with spatial degrees of freedom. The whole setup is autonomous and can be studied using quantum scattering theory. The work to switch on and off the interaction now is due to the interaction between the system and the kinetic energy of the incident particle. Then, if the units are in thermal equilibrium, this energy exchange becomes heat, and thermalization is recovered. However, we have proven that thermalization requires that the wave function of the incident particles is narrow in momentum representation, i.e., the dispersion of the momentum must be very small. This condition conflicts with the requirement that the particle is localized in space in order to observe well-defined collisions and also poses the fundamental question of the nature of the wave function of particles that effuse from a gas at equilibrium.

Join Zoom Meeting https://cam-ac-uk.zoom.us/j/81067386873?pwd=enExTFBpY3EvZDFtV2NBSGxxMVBSZz09

Meeting ID: 810 6738 6873 Passcode: 3141