Open AccessHusimi function and Wehrl entropy in thermo field dynamics
Author(s) -
Shuai Wang,
Zhang Bing-yun,
Yunhai Zhang
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.1775
Subject(s) - physics , coherent states , entropy (arrow of time) , phase space , von neumann entropy , quantum mechanics , joint quantum entropy , quantum state , observable , quantum relative entropy , quantum , quantum discord , classical mechanics , statistical physics , quantum dynamics , quantum entanglement
Using the quantum phase space technique and the information-theory like the Wehrl entropy, the Husimi function and the Wehrl entropy of the quantum pure states and the corresponding mixed states in thermo field dynamics are studied. It is found that the Husimi function and the Wehrl entropy of the thermal coherent state agree with that of the corresponding mixed states. And the Wehrl entropy of thermal coherent state is not related with the displacement factor. Therefore for a quantum system, the quantum fluctuations of the observable quantities and corresponding uncertainty relation are also not related with the displacement factor in the thermal coherent state.