Open AccessSTATISTICAL ANGLE OF QUANTUM MIXED STATES
Author(s) -
Dan Zhu,
Renchuan Wang,
Guixing Wang
Publication year - 1992
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.41.543
Subject(s) - quantum , physics , quantum state , quantum relative entropy , divergence (linguistics) , statistical physics , trigonometric functions , quantum discord , quantum mechanics , mathematics , open quantum system , geometry , linguistics , philosophy
The statistical angle between quantum pure stages has been generalized to quantum mixed states. For the case of a single mixed state, it leads to a concept of divergence angle. A criterion for pure state is obtained. In the quantum measurement the information function is the squared cosine of statistical angle between the quantum system and the instrument. The entropy increase during the measurement process appears to be the expanding of the divergence angle.