Work extraction from microcanonical bath
Armen E. Allahverdyan
Yerevan Phys. Inst. (Arménie) et Lab. Phys. Stat. Syst. Complexes (Le Mans)
Lundi 11/06/2012, 14:00
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
How much work can be extracted from a physical system? This is one of the basic problems in thermodynamics, since it provides the physical meaning of the free energy. Here we discuss the maximal work extractable via a cyclic Hamiltonian process from a positive-temperature microcanonical state of a macroscopic spin bath. The work is much smaller than the total energy of the bath, but can be still much larger than the energy of a single bath spin. The results apply for those cases, where the canonical state is unstable (e.g., due to a negative specific heat) and the microcanonical state is the only description of equilibrium. For a system coupled to a microcanonical bath the concept of the free energy still applies, but instead of the von Neumann (Shannon-Gibbs) entropy the expression for the free energy contains a linear entropy. A unifying view on both the von Neumann entropy and the linear entropy is provided within the computational complexity theory. \ \ Coauthor: Karen V. Hovhannisyan
Contact : Gregoire MISGUICH


Retour en haut