Quantum phase transitions via density-functional theory: Extension to the degenerate case

A. Nagy, E. Romera

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article number042515
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume88
Issue number4
DOIs
Publication statusPublished - Oct 28 2013

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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