Coupled physical systems

Karl Blum

You-Yang Xu, Jiangbin Gong, Wu‐Ming Liu

Quantum thermodynamic quantities, normally formulated with the assumption of weak system-bath coupling (SBC), can often be contested in physical circumstances with strong SBC. This work presents an alternative treatment that enables us to use standard concepts based on weak SBC to tackle with quantum thermodynamics with strong SBC. Specifically, via a physics-motivated mapping between strong and weak SBC, we show that it is possible to identify thermodynamic quantities with arbitrary SBC, including work and heat that shed light on the first law of thermodynamics with strong SBC. Quantum fluctuation theorems, such as the Tasaki-Crooks relation and the Jarzynski equality are also shown to be extendable to strong SBC cases. Our theoretical results are further illustrated with a working example.

Karl Blum

Emmanuel Kanambaye

In this paper, we prove a theorem that imposes that certain coupled physical systems (particles or fields) have non-commuting observables even without postulating canonical commutation relation. More precisely, we prove a theorem that ensures that it is forbidden for certain coupled physical systems to exist in a physical world as classical systems (i.e. systems describable by classical mechanics); we will call the theorem on Non-Classicality. We will see in the present paper and in next papers, that the Theorem on Non-Classicality has important consequences among which the implication of a Quantum Mechanics more fundamental than Standard Quantum Mechanics.

Gordon Baym, Tomoki Ozawa

Cold atomic Bose-Einstein systems in the presence of simulated Rashba- Dresselhaus spin-orbit coupling exhibit novel physical features. With pure in-plane Rashba coupling the system is predicted in Bogoliubov-Hartree-Fock to have a stable Bose condensate below a critical temperature, even though the effective density of states is two-dimensional. In addition the system has a normal state at all temperatures. We review here the new physics when the system has such spin-orbit coupling, and discuss the nature of the finite temperature condensation phase transition from the normal to condensed phases.

Karl Blum