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We theoretically consider the effect of the atomic source's momentum width on the efficiency of Bragg mirrors and beamsplitters and, more generally, on the phase sensitivity of Bragg pulse atom interferometers. By numerical optimization, we show that an atomic cloud's momentum width places a fundamental upper bound on the maximum transfer efficiency of a Bragg mirror pulse, and furthermore limits the phase sensitivity of a Bragg pulse atom interferometer. We quantify these momentum width effects, and precisely compute how mirror efficiencies and interferometer phase sensitivities vary as functions of Bragg order and source type. Our results and methodology allow for an efficient optimization of Bragg pulses and the comparison of different atomic sources, and will help in the design of large momentum transfer Bragg mirrors and beamsplitters for use in atom-based inertial sensors. [ABSTRACT FROM AUTHOR]

We present the first realization of a solitonic atom interferometer. A Bose-Einstein condensate of 1 × 104 atoms of rubidium-85 is loaded into a horizontal optical waveguide. Through the use of a Feshbach resonance, the s-wave scattering length of the 85Rb atoms is tuned to a small negative value. This attractive atomic interaction then balances the inherent matter-wave dispersion, creating a bright solitonic matter wave. A Mach-Zehnder interferometer is constructed by driving Bragg transitions with the use of an optical lattice colinear with the waveguide. Matter-wave propagation and interferometric fringe visibility are compared across a range of s-wave scattering values including repulsive, attractive and noninteracting values. The solitonic matter wave is found to significantly increase fringe visibility even compared with a noninteracting cloud. [ABSTRACT FROM AUTHOR]

We present a precision gravimeter based on coherent Bragg diffraction of freely falling cold atoms. Traditionally, atomic gravimeters have used stimulated Raman transitions to separate clouds in momentum space by driving transitions between two internal atomic states. Bragg interferometers utilize only a single internal state, and can therefore be less susceptible to environmental perturbations. Here we show that atoms extracted from a magneto-optical trap using an accelerating optical lattice are a suitable source for a Bragg atom interferometer, allowing efficient beamsplitting and subsequent separation of momentum states for detection. Despite the inherently multi-state nature of atom diffraction, we are able to build a Mach-Zehnder interferometer using Bragg scattering which achieves a sensitivity to the gravitational acceleration of Δg/g = 2.7 x 10-9 with an integration time of 1000 s. The device can also be converted to a gravity gradiometer by a simple modification of the light pulse sequence. [ABSTRACT FROM AUTHOR]

In our original paper (Altin et al 2011 New J. Phys. 13 065020), we presented the results from a Ramsey atom interferometer operating with an optically trapped sample of up to 106 Bose-condensed 87Rb atoms in the mF = 0 clock states. We were unable to observe projection noise fluctuations on the interferometer output, which we attribute to the stability of our microwave oscillator and background magnetic field. Numerical simulations of the Gross-Pitaevskii equations for our system show that dephasing due to spatial dynamics driven by interparticle interactions accounts for much of the observed decay in fringe visibility at long interrogation times. The simulations show good agreement with the experimental data when additional technical decoherence is accounted for, and suggest that the clock states are indeed immiscible. With smaller samples of 5×104 atoms, we observe a coherence time of τ = 1.0+0.5 -0.3 s. [ABSTRACT FROM AUTHOR]

We present a Ramsey-type atom interferometer operating with an optically trapped sample of 106 Bose-condensed 87Rb atoms. We investigate this interferometer experimentally and theoretically with an eye to the construction of future high precision atomic sensors. Our results indicate that, with further experimental refinements, it will be possible to produce and measure the output of a sub-shot-noise-limited, large atom number BEC-based interferometer. The optical trap allows us to couple the ∣F = 1, mF = 0⟩→∣F = 2, mF = 0⟩ clock states using a single photon 6.8 GHz microwave transition, while state selective readout is achieved with absorption imaging. We analyse the process of absorption imaging and show that it is possible to observe atom number variance directly, with a signal-to-noise ratio ten times better than the atomic projection noise limit on 106 condensate atoms. We discuss the technical and fundamental noise sources that limit our current system, and present theoretical and experimental results on interferometer contrast, de-phasing and miscibility. [ABSTRACT FROM AUTHOR]

We describe our experimental setup for creating stable Bose–Einstein condensates (BECs) of 85Rb with tunable interparticle interactions. We use sympathetic cooling with 87Rb in two stages, initially in a tight Ioffe–Pritchard magnetic trap and subsequently in a weak, large-volume, crossed optical dipole trap, using the 155 G Feshbach resonance to manipulate the elastic and inelastic scattering properties of the 85Rb atoms. Typical 85Rb condensates contain 4×104 atoms with a scattering length of a=+200a0. Many aspects of the design presented here could be adapted to other dual-species BEC machines, including those involving degenerate Fermi–Bose mixtures. Our minimalist apparatus is well suited to experiments on dual-species and spinor Rb condensates, and has several simplifications over the 85Rb BEC machine at JILA, which we discuss at the end of this article. [ABSTRACT FROM AUTHOR]

A Bose-Einstein condensate is used as an atomic source for a high precision sensor. A 5 ? 106 atom F = 1 spinor condensate of 87Rb is released into free fall for up to 750 ms and probed with a T = 130 ms Mach-Zehnder atom interferometer based on Bragg transitions. The Bragg interferometer simultaneously addresses the three magnetic states |mf = 1, 0, -1〉, facilitating a simultaneous measurement of the acceleration due to gravity with a 1000 run precision of Δg/g = 1.45 ? 10-9 and the magnetic field gradient to a precision of 120 pT/m. [ABSTRACT FROM AUTHOR]

This paper presents the first realization of a simultaneous 87Rb–85Rb Mach–Zehnder atom interferometer with Bose-condensed atoms. A number of ambitious proposals for precise terrestrial and space based tests of the weak equivalence principle rely on such a system. This implementation utilizes hybrid magnetic-optical trapping to produce spatially overlapped condensates with a repetition rate of 20 s. A horizontal optical waveguide with co-linear Bragg beamsplitters and mirrors is used to simultaneously address both isotopes in the interferometer. We observe a non–linear phase shift on a non-interacting 85Rb interferometer as a function of interferometer time, T, which we show arises from inter-isotope scattering with the co-incident 85Rb interferometer. A discussion of implications for future experiments is given. [ABSTRACT FROM AUTHOR]