Unusual decoherence in qubit measurements with a Bose-Einstein condensate

Autor:	Sokolovski, D., Gurvitz, S. A.
Rok vydání:	2008
Předmět:	Quantum Physics Condensed Matter - Mesoscale and Nanoscale Physics
Druh dokumentu:	Working Paper
DOI:	10.1103/PhysRevA.79.032106
Popis:	We consider an electrostatic qubit located near a Bose-Einstein condensate (BEC) of noninteracting bosons in a double-well potential, which is used for qubit measurements. Tracing out the BEC variables we obtain a simple analytical expression for the qubit's density-matrix. The qubit's evolution exhibits a slow ($\propto1/\sqrt{t}$) damping of the qubit's coherence term, which however turns to be a Gaussian one in the case of static qubit. This stays in contrast to the exponential damping produced by most classical detectors. The decoherence is, in general, incomplete and strongly depends on the initial state of the qubit. Comment: 5 pages, additional explanations related to experimental realization are added, typos corrected, Phys. Rev. A, in press
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/0807.4440 Zobrazit plný text záznamu View this record from Arxiv