| 1. |
- Anandan, Jeeva S., et al.
(författare)
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Reply to Comment on `Geometric phases for mixed states in interferometry'
- 2002
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 89, s. 268902-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The only difference between Bhandari's viewpoint and ours [Phys. Rev. Lett. 85, 2845 (2000)] is that our phase is defined modulo 2π, whereas Bhandari argues that two phases that differ by 2π n, n integer, may be distinguished experimentally in a history-dependent manner. (Reply to the Comment in Phys. Rev. Lett. 89, 268901 (2001) by R. Bhandari.)
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| 2. |
- Ericsson, Marie, et al.
(författare)
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Generalization of the geometric phase to completely positive maps
- 2003
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 67:2, s. 020101(R)-
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Tidskriftsartikel (refereegranskat)abstract
- We generalize the notion of relative phase to completely positive maps with known unitary representation, based on interferometry. Parallel transport conditions that define the geometric phase for such maps are introduced. The interference effect is embodied in a set of interference patterns defined by flipping the environment state in one of the two paths. We show for the qubit that this structure gives rise to interesting additional information about the geometry of the evolution defined by the CP map.
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| 3. |
- Ericsson, Marie, et al.
(författare)
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Mixed state geometric phases, entangled systems, and local unitary transformations
- 2003
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 91:9, s. 090405-
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Tidskriftsartikel (refereegranskat)abstract
- The geometric phase for a pure quantal state undergoing an arbitrary evolution is a "memory'' of the geometry of the path in the projective Hilbert space of the system. We find that Uhlmann's geometric phase for a mixed quantal state undergoing unitary evolution not only depends on the geometry of the path of the system alone but also on a constrained bi-local unitary evolution of the purified entangled state. We analyze this in general, illustrate it for the qubit case, and propose an experiment to test this effect. We also show that the mixed state geometric phase proposed recently in the context of interferometry requires uni-local transformations and is therefore essentially a property of the system alone.
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| 4. |
- Sjöqvist, Erik, et al.
(författare)
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Geometric phases for mixed states in interferometry
- 2000
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 85:14, s. 2845-2849
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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