| Issue |
Europhys. Lett.
Volume 62, Number 6, June 2003
|
|
|---|---|---|
| Page(s) | 782 - 788 | |
| Section | General | |
| DOI | https://doi.org/10.1209/epl/i2003-00440-4 | |
| Published online | 01 June 2003 | |
Phases of quantum states in completely positive non-unitary evolution
1
Departamento de Física-Matemática, Instituto de Física Universidade de São Paulo - C.P. 66318 05315-970 São Paulo, São Paulo, Brazil
2
Departamento de Física, Instituto de Ciências Exatas Universidade Federal de Minas Gerais - C.P. 702 30161-970 Belo Horizonte, Minas Gerais, Brazil
Corresponding author: jgfaria@fma.if.usp.br
Received:
30
October
2002
Accepted:
25
April
2003
We define an operational notion of phases in interferometry for a quantum system undergoing a completely positive non-unitary evolution. This definition is based on the concepts of quantum measurement theory. The suitable generalization of the Pancharatnan connection allows us to determine the dynamical and geometrical parts of the total phase between two states linked by a completely positive map. These results reduce to the known expressions of the total, dynamical and geometrical phases for pure and mixed states evolving unitarily.
PACS: 03.65.Vf – Phases: geometric; dynamic or topological / 03.65.Ta – Foundations of quantum mechanics; measurement theory / 03.65.Yz – Decoherence; open systems; quantum statistical methods
© EDP Sciences, 2003
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