Abstract
The residual properties, after cooling from a high temperature to T=0 K, of a system of identical and independent two-level systems are analyzed. A general criterion to know whether a given cooling law will lead to a nonvanishing residual population is derived. After defining in a precise way the condition of slow cooling, asymptotic expressions for the residual population and entropy are obtained for a family of cooling laws. It is shown that the expressions for the residual properties, and their own existence, depend quite strongly on the cooling procedure.
- Received 16 November 1990
DOI:https://doi.org/10.1103/PhysRevB.43.8350
©1991 American Physical Society
