Thermodynamics and phase transitions in dissipative and active Morse chains
Abstract
We study the evolution of a simple onedimensional chain of N=4 particles with Morse interactions and periodic boundary conditions which are imbedded into a heat bath creating dissipation and noise. The investigation is concentrated on thermodynamic properties for equilibrium, nearequilibrium and farequilibrium conditions. For the thermodynamic equilibrium, created by white noise and passive friction obeying Einstein's fluctuation dissipation relation, we find a standard phase diagram. By applying active friction forces the system is driven to stationary nonequilibrium states, creating conditions where various selfsustained oscillations are excited. Thermodynamic quantities like energy, pressure and entropy are calculated near equilibrium, around a critical distance from equilibrium and far from equilibrium. We observe maximal order (minimum entropy) in certain region of the noise temperature, a phenomenon which is reminiscent of stochastic resonance. With increasing distance from equilibrium new "phases" corresponding to the existence of several attractors of the dynamical stem appear.
 Publication:

European Physical Journal B
 Pub Date:
 April 2005
 DOI:
 10.1140/epjb/e2005001512
 Bibcode:
 2005EPJB...44..509C
 Keywords:

 Entropy;
 Stochastic Resonance;
 Thermodynamic Quantity;
 Critical Distance;
 Heat Bath