Effect of trap anharmonicity on a free-oscillation atom interferometer

Abstract

A free-oscillation interferometer uses atoms confined in a harmonic trap. Bragg scattering from an off-resonant laser is used to split an atomic wave function into two separated packets. After one or more oscillations in the trap, the wave packets are recombined by a second application of the Bragg laser to close the interferometer. Anharmonicity in the trap potential can lead to a phase shift in the interferometer output. In this paper, analytical expressions for the anharmonic phase are derived at leading order for perturbations of arbitrary power in the position coordinate. The phase generally depends on the initial position and velocity of the atom, which are themselves typically uncertain. This leads to degradation in the interferometer performance, and can be expected to limit the use of a cm-scale device to interaction times of about 0.1 s. Methods to improve performance are discussed.Comment: 8 pages, 5 figure

Effect of interparticle interaction in a free-oscillation atomic interferometer

“…For example, in the presence of attractive interactions these allow for the formation of bright soliton states, which are nondispersive and have been suggested as good candidates for the creation of macroscopic spatial superpositions [11][12][13][14]. Furthermore, the ubiquitous presence of harmonic traps for ultracold atoms has led to new ideas for interferometry designs based on the periodic trap dynamics [15][16][17][18]. Such schemes, which present a viable approach to atomic interferometry require often minimal experimental efforts and are referred to as free oscillation atom interferometers.…”

Revival of Raman coherence of trapped atoms

“…In addition, we predict that for traps with weak anharmonicity, quantum control methods such as echo and dynamical decoupling can increase the revival amplitude, thereby mitigating the deterioration of the coherence due to the trap anharmonicity and elastic atomic collisions. Raman atomic coherence in a trap is closely related to the field free-oscillation atom interferometry [26,29,[31][32][33][34] and may help to further analyze the limitations and properties of such interferometers. Our results apply also to light storage [12,50,51,53], where the stored atomic coherence is released in the form of light emitted in a controlled direction.…”

“…By changing the angle α, the momentum recoilhk eff can be varied between practically zero and 2hk. This allows coupling to the external degrees of freedom of the atoms and the possibility of implementation of spatial multi-mode quantum memory [23,24].Raman atomic coherence in a trap is closely related to the fringe contrast of guided interferometers [25][26][27][28], and more specifically free-oscillation atom interferometers [26,[29][30][31][32][33][34]. These rely on the classical turning points of an underlying harmonic potential for the mirroring of the wave packets.…”

Systematic effects in two-dimensional trapped matter-wave interferometers

“…TMIs also provide resilience to systematics: for harmonic potentials, the accumulated phase has zero contribution from the confining potential and is insensitive to the initial velocity of the wavepackets. However, this demands that the confining potential is well-controlled [26]. The commonpath geometry also makes TMIs generally less sensitive to external forces, e.g.…”