A dynamical phase transition between the dissipative and the non-dissipative solutions of a thermal process and its consequences
K. Gambár

Dennis Gabor Applied University, Etele ut 68, H-1115 Budapest, Hungary

Abstract: Dynamic phase transitions between non-dissipative and dissipative processes are discussed from different viewpoints. Thermal and mechanical examples are shown to illustrate the transition pointing out their realistic behavior. In the thermal case, an abstract scalar field has been introduced to generate a dynamical temperature and a covariant field equation to describe the heat propagation with finite speed.less than the speed of light.of action. It has been shown how this scalar field can be connected to the usual temperature (local equilibrium temperature) and the Fourier.s heat conduction. The dynamical phase transition is in between these two kinds of . wave and non-wave . propagation. In the mechanical example the phase transition is shown on a .stretched string on a rotating wheel. system. In both cases similar Klein-Gordon equations with a .negative mass. term describe the spinodal instability. It seems interesting that the thermal case may have an important role in the definition of a really dynamical temperature in cosmology.