Quantum State Preparation of Spin Ensembles by Continuous Measurement and Feedback
Abstract
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.
Additional Information
© 2007 Imperial College Press. The authors would like to thank Luc Bouten and JM Geremia for many fruitful discussions. This work was supported by the Australian Research Council, the ARO and the Caltech MURI Center for Quantum Networks. JKS acknowledges a Hertz fellowship. Some of this chapter was originally published (in extended form) in Ref. 64. These parts are reproduced here with permission of Institute of Physics Publishing Ltd.Additional details
- Eprint ID
- 20671
- Resolver ID
- CaltechAUTHORS:20101104-105022806
- Australian Research Council
- Army Research Office (ARO)
- NSF
- Fannie and John Hertz Foundation
- Created
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2010-11-04Created from EPrint's datestamp field
- Updated
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2023-06-20Created from EPrint's last_modified field