Quantum state preparation of spin ensembles by continuous measurement and feedback

Ramon van Handel, John K. Stockton, Hideo Mabuchi, Howard M. Wiseman

Research output: Chapter in Book/Report/Conference proceedingChapter


Beginning with a microscopic model for the interaction between atoms and the electromagnetic field, we describe how stochastic equations for the state of the atomic ensemble conditioned upon homodyne measurement of the field can be derived. We investigate the evolution of the stochastic state both in the short time scale, where a description in terms of continuous variables (spin quadratures) is possible, and in the longer time scale where this description breaks down. Next we discuss general principles of quantum feedback control, and apply them to quantum state preparation in the atomic ensemble. We consider three cases: producing spin-squeezed states, preparing Dicke states (the long-time limit), and producing twin-ensemble squeezing. Where appropriate, we emphasize relations with experiments.

Original languageEnglish (US)
Title of host publicationQuantum Information with Continuous Variables of Atoms and Light
PublisherImperial College Press
Number of pages24
ISBN (Electronic)9781860948169
ISBN (Print)186094776X, 9781860947605
StatePublished - Jan 1 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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