Adiabatic metastability
Abstract
We study the effect of thermal isolation on metastability, describing the metastability in the Ginzburg-Landau formalism. We find that metastability is always strengthened by thermal isolation. For an isolated body it is thus even possible to obtain, in principle, certain new kinds of quasithermodynamic states stabilized by virtue of their isolation, which would not be attainable for the body kept at any constant temperature. These are configurations where, although the free energy is at local maximum, the total (negative) entropy is at a minimum. We interpret this to mean that the body is metastable when in isolation, but becomes unstable in contact with a heat bath, nevertheless at the same temperature. The systems in question are small in the sense that the energy involved with the metastability must not be negligible relative to the heat capacity. The example of a thin type-1 superconducting sheet is examined. By isolating the body in the usual metastable (``superheated'') state in the neighborhood of the superheating field and then raising the magnetic field, one may attain the ``isolation metastable'' state.
- Publication:
-
Physical Review A
- Pub Date:
- April 1989
- DOI:
- 10.1103/PhysRevA.39.3646
- Bibcode:
- 1989PhRvA..39.3646S
- Keywords:
-
- Adiabatic Conditions;
- Landau-Ginzburg Equations;
- Metastable State;
- Thermodynamic Properties;
- Entropy;
- Phase Diagrams;
- Specific Heat;
- Superconductors;
- Superheating;
- Wave Functions;
- Thermodynamics and Statistical Physics;
- 05.70.Fh;
- 64.60.My;
- 74.20.De;
- Phase transitions: general studies;
- Metastable phases;
- Phenomenological theories