Differential atom interferometry beyond the standard quantum limit

Journal Article · Sun Jan 15 04:00:00 EST 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.73.0· OSTI ID:20786785

Eckert, K ^[1]; Hyllus, P ^[1]; Bruss, D ^[1]; Poulsen, U V ^[1]; Lewenstein, M ^[1]; Jentsch, C; Mueller, T; Rasel, E M; Ertmer, W ^[2]

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1. Institut fuer Theoretische Physik, Universitaet Hannover, D-30167 Hannover (Germany)
2. Institut fuer Quantenoptik, Universitaet Hannover, D-30167 Hannover (Germany)

We analyze methods designed to go beyond the standard quantum limit for a class of atomic interferometers, where the quantity of interest is the difference of phase shifts obtained by two independent atomic ensembles. An example is given by an atomic Sagnac interferometer, where for two ensembles propagating in opposite directions in the interferometer this phase difference encodes the angular velocity of the experimental setup. We discuss methods of separately or jointly squeezing observables of the two atomic ensembles, and compare in detail the advantages and drawbacks of such schemes. In particular, we show that the method of joint squeezing may improve the variance by up to a factor of 2. We take into account fluctuations of the number of atoms in both the preparation and the measurement stage, and obtain bounds on the difference between the numbers of atoms in the two ensembles, as well as on the detection efficiency, which have to be fulfilled in order to surpass the standard quantum limit. Under realistic conditions, the performance of both schemes can be improved significantly by reading out the phase difference via a quantum nondemolition measurement. Finally, we discuss a scheme using macroscopically entangled ensembles.

• OSTI ID: 20786785
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 73; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR VELOCITY
ATOMS
COMPARATIVE EVALUATIONS
EFFICIENCY
FLUCTUATIONS
INTERFEROMETERS
INTERFEROMETRY
OPTICS
PERFORMANCE
PHASE SHIFT
QUANTUM ENTANGLEMENT