In order to describe quantum heat engines, here we systematically study isothermal and isochoric processes for quantum thermodynamic cycles. Based on these results the quantum versions of both the Carnot heat engine and the Otto heat engine are defined without ambiguities. We also study the properties of quantum Carnot and Otto heat engines in comparison with their classical counterparts. Relat...

We consider reversible work extraction from two finite reservoirs of perfect gases with given initial temperatures T+ and T−, when the final values of the temperatures are known but they can be assigned to specific reservoirs only probabilistically. Using inference, we characterize the reduced performance resulting from this uncertainty. The estimates for the efficiency reveal that uncertainty ...

Gromov proposed to extract the (differential) geometric content of a sub-riemannian space exclusively from its Carnot-Carathéodory distance. One of the most striking features of a regular sub-riemannian space is that it has at any point a metric tangent space with the algebraic structure of a Carnot group, hence a homogeneous Lie group. Siebert characterizes homogeneous Lie groups as locally co...

A mechanism of electron-mediated pumping heat in the absence net charge transfer is proposed. It may be realized charge-neutral electron systems, such as graphene, coupled to an external electric potential. The flow this cycle not accompanied by a buildup voltage along system, which offers advantages over traditional thermoelectric cooling setups. efficiency and magnitude flux are studied hydro...

Quantum heat cycles and quantum refrigerators are analyzed using various systems as their working mediums. For example, to evaluate the efficiency work done of Carnot cycle in regime, one can consider harmonic oscillator a medium. all these well-defined substances (which commutative space structure), engine is not up mark efficiency. So, inevitable question arise, observe catalytic effect on en...

We prove non local Hardy inequalities on Carnot groups and Riemannian manifolds, relying on integral representations of fractional Sobolev norms. AMS numbers 2000: Primary: 46E35. Secondary: 35R11, 42B35, 58J35.

This study presents an experimental comparison of energy, exergy flow and second law efficiency of R22 and its substitute R436b (hydrocarbon mixture of 52% of propane (R290) 48% of isobutene (R600a)), vapour compression refrigeration cycles. The vapour compression refrigeration cycle was initially designed to operate with R22. The primary objective of this paper is to analyze the system process...