Geometric phases for mixed states in interferometry.
We provide a physical prescription based on interferometry for introducing the total phase of a mixed state undergoing unitary evolution, which has been an elusive concept in the past. We define the parallel transport condition that provides a connection form for obtaining the geometric phase for mixed states. The expression for the geometric phase for mixed state reduces to well known formulas in the pure state case when a system undergoes noncyclic and unitary quantum evolution.
Sjöqvist
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E
Department of Quantum Chemistry, Uppsala University, Box 518, Se-751 20 Uppsala, Sweden.
Pati
A K
AK
Ekert
A
A
Anandan
J S
JS
Ericsson
M
M
Oi
D K
DK
Vedral
V
V