Inertial sensing with quantum gases: a comparative performance study of condensed versus thermal sources for atom interferometry

Abstract

Quantum sensors based on light pulse atom interferometers allow for measurements of inertial and electromagnetic forces such as the accurate determination of fundamental constants as the fine structure constant or testing foundational laws of modern physics as the equivalence principle. These schemes unfold their full performance when large interrogation times and/or large momentum transfer can be implemented. In this article, we demonstrate how interferometry can benefit from the use of Bose–Einstein condensed sources when the state of the art is challenged. We contrast systematic and statistical effects induced by Bose–Einstein condensed sources with thermal sources in three exemplary science cases of Earth- and space-based sensors. Graphic abstract

Stern-Gerlach Interferometry for Tests of Quantum Gravity and General Applications

“…An additional advantage that these sensors offer is the precise determination of the fundamental constants of Nature (see for instance [62]). The key experimental factors, as always, include long interferometric times and the implementation of large momentum transfer techniques [63]. As to what constitutes the current state-of-the-art, the figure of merit for these quantum sensing devices, the tools and techniques available to implement these devices in real time and certain experimental challenges that are yet to be addressed, the reader is encouraged to consult [63].…”

“…The key experimental factors, as always, include long interferometric times and the implementation of large momentum transfer techniques [63]. As to what constitutes the current state-of-the-art, the figure of merit for these quantum sensing devices, the tools and techniques available to implement these devices in real time and certain experimental challenges that are yet to be addressed, the reader is encouraged to consult [63]. Of particular interest to the scientific community has been gravity measurements using cold-atom sensors.…”

All-Optical Matter-Wave Lens using Time-Averaged Potentials

“…Up to T I = 100 ms and σ a (1 s) = 10 −8 m s −2 , the molasses outperforms evaporatively cooled atoms or BECs due the duration of the evaporation adding to the cycle time and associated losses. In this time regime, the latter can still be beneficial for implementing large momentum transfer beam splitters [36, 38-40, 42, 43] reducing σ a (τ ) or suppressing systematic errors [20,[31][32][33][34]74] which is not represented in our model and beyond the scope of this paper. According to the curves, exploiting higher T I for increased performance requires evaporatively cooled atoms or BECs.…”

“…Therefore, matter-wave sensors require sources with a high flux of large cold atomic ensembles to obtain fast repetition rates. Bose-Einstein condensates (BECs) are investigated to control systematic effects related to residual motion at a level lower than a few parts in 10 9 of Earth's gravitational acceleration [20,[31][32][33][34]. In addition, due to their narrower velocity distribution [35], BECs offer higher beam splitting efficiencies and thus enhanced contrast [23,36,37], especially for large momentum transfer [36,[38][39][40][41][42][43].…”

Bose-Einstein condensates in microgravity and fundamental tests of gravity

“…However, due to the cloud's finite momentum spread, the it will start to expand drastically after release. Indeed, an order of magnitude estimation for cold rubidium atoms indicates a size of several tenth of centimeters after ten seconds of interferometer time [193]. Atom clouds of large extent in position and momentum space make long-time interferometry experimentally difficult if not impossible for the following reasons: A cloud with broad momentum distribution cannot be addressed resonantly with the laser beams, leading to velocity selectivity [23] and con-sequently inefficient diffraction.…”