Coexistence of long-range order for two observables at finite temperatures

Authors
Macris, N Piguet, CA
Citation
N. Macris et Ca. Piguet, Coexistence of long-range order for two observables at finite temperatures, J PHYS A, 32(5), 1999, pp. 749-755
Citations number
8
Categorie Soggetti
Physics
Journal title
JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL
ISSN journal
03054470 → ACNP
Volume
32
Issue
5
Year of publication
1999
Pages
749 - 755
Database
ISI
SICI code
0305-4470(19990205)32:5<749:COLOFT>2.0.ZU;2-3
Abstract
We give a criterion for the simultaneous existence or non-existence of two long-range orders for two observables, at finite temperatures, for quantum lattice many body systems. Our analysis extends previous results of Tian (1 997 J. Phys. A: Math. Gen. 30 841) limited to the ground state of similar m odels. The proof involves an inequality of Dyson-Lieb-Simon (1978 J. Star. Phys. 18 335) which connects the Duhamel two-point function to the usual co rrelation function. An application to the special case of the Holstein mode l is discussed.