According to the recently proposed density-functional analog of quantum phase transitions (QPTs) the "density" determines the "control parameter" (corresponding to the density-functional theory "external potential"). It was also proved that in the nondegenerate case there is a one-to-one map between the ground-state wave function and the control parameter. It is now shown that there is a one-to-one map between the ground-state subspace and the control parameter. It is pointed out that there is a one-to one map between the subspace density and the control parameter. The Rényi entropies are proved to be strictly monotonic functions of the control parameter in the neighborhood of the transition point. These properties are illustrated with the Dicke model which exhibits a QPT from a normal phase (nondegenerate) to the superradiant case (degenerate) in the thermodynamic limit.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - Oct 28 2013|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics