Europhys. Lett.
Volume 74, Number 6, June 2006
Page(s) 958 - 964
Section General
Published online 17 May 2006
Europhys. Lett., 74 (6), pp. 958-964 (2006)
DOI: 10.1209/epl/i2006-10057-1

Geometric phase in open two-level system

Z. S. Wang1, L. C. Kwek1, 2, C. H. Lai1 and C. H. Oh1

1  Department of Physics, National University of Singapore 2 Science Drive 3, Singapore 117542
2  Nanyang Technological University, National Institute of Education 1 Nanyang Walk, Singapore 637616

received 8 February 2006; accepted in final form 24 April 2006
published online 17 May 2006

A mapping is established in connecting density matrices, associated with an evolution of a quantum open system, with vector ray in a complex projective Hilbert space. By using the corresponding vector ray to represent the open two-level system, we may observe the geometric phase for the open two-level system. The geometric phase of the open two-level system depends only on the smooth (open or closed) curve in the complex projective Hilbert space of ray, which is formulated entirely in terms of geometric structures on this space.

03.65.Vf - Phases: geometric; dynamic or topological.
03.65.Yz - Decoherence; open systems; quantum statistical methods.

© EDP Sciences 2006