Mixed state geometric phases, entangled systems, and local unitary transformations
2003 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 91, no 9, 090405- p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2003. Vol. 91, no 9, 090405- p.
Geometric phase, Uhlmann holonomy, mixed quantum states
Research subject Physics
IdentifiersURN: urn:nbn:se:uu:diva-45724DOI: 10.1103/PhysRevLett.91.090405PubMedID: 14525166OAI: oai:DiVA.org:uu-45724DiVA: diva2:73632
Also in Virtual Journal of Quantum Information, September issue 20032006-12-142006-12-142011-10-05