Quantum phase transitions without thermodynamic limits
File(s)
Author(s)
Brody, DC
Hook, DW
Hughston, LP
Type
Journal Article
Abstract
A new microcanonical equilibrium state is introduced for quantum systems with finite-dimensional state spaces. Equilibrium is characterized by a uniform distribution on a level surface of the expectation value of the Hamiltonian. The distinguishing feature of the proposed equilibrium state is that the corresponding density of states is a continuous function of the energy, and hence thermodynamic functions are well defined for finite quantum systems. The density of states, however, is not in general an analytic function. It is demonstrated that generic quantum systems therefore exhibit second-order phase transitions at finite temperatures.
Version
Accepted version
Date Issued
2007-08-08
Citation
Proc Roy Soc A, 2007, 463 (2084), pp.2021-2030
ISSN
1364-5021
Publisher
ROYAL SOCIETY
Start Page
2021
End Page
2030
Journal / Book Title
Proc Roy Soc A
Volume
463
Issue
2084
Copyright Statement
© 2007 The Royal Society
Source Volume Number
463
Subjects
microcanonical equilibrium
quantum phase space
thermalization
decoherence
topological phase transitions
STATISTICAL MECHANICS
ENSEMBLE