Doppler compensation for cavity-based atom interferometry.

We propose and demonstrate a scheme for Doppler compensated optical cavity enhancement of atom interferometers at significantly increased mode diameters. This overcomes the primary limitations in cavity enhancement for atom interferometry, circumventing the cavity linewidth limit and enabling spatial mode filtering, power enhancement, and a large beam diameter simultaneously. This approach combines a magnified linear cavity with an intracavity Pockels cell. The Pockels cell induces a voltage-controlled birefringence allowing the cavity mode frequencies to follow the Raman lasers as they track gravitationally induced Doppler shifts, removing the dominant limitation of current cavity enhanced systems. A cavity is built to this geometry and shown to simultaneously realise Doppler compensation, a 5.8 ± 0.15 mm1/e2 diameter beam waist and an enhancement factor of >5× at a finesse of 35. Tuneable Gouy phase enables the suppression of higher order spatial modes and the avoidance of regions of instability. Atom interferometers will see increased contrast at extended interferometry times along with power enhancement and the reduction of optical aberrations. This is relevant to power constrained applications in quantum technology, alongside the absolute performance requirements of fundamental science.

Magneto-optical trapping in a near-suface borehole.

Borehole gravity sensing can be used in a number of applications to measure features around a well, including rock-type change mapping and determination of reservoir porosity. Quantum technology gravity sensors, based on atom interferometry, have the ability to offer increased survey speeds and reduced need for calibration. While surface sensors have been demonstrated in real world environments, significant improvements in robustness and reductions to radial size, weight, and power consumption are required for such devices to be deployed in boreholes. To realise the first step towards the deployment of cold atom-based sensors down boreholes, we demonstrate a borehole-deployable magneto-optical trap, the core package of many cold atom-based systems. The enclosure containing the magneto-optical trap itself had an outer radius of (60 ± 0.1) mm at its widest point and a length of (890 ± 5) mm. This system was used to generate atom clouds at 1 m intervals in a 14 cm wide, 50 m deep borehole, to simulate how in-borehole gravity surveys are performed. During the survey, the system generated, on average, clouds of (3.0 ± 0.1) × 105 87Rb atoms with the standard deviation in atom number across the survey observed to be as low as 8.9 × 104.

A Preliminary Evaluation of Virginia Fresh Match: Impacts and Demographic Considerations for Future Fruit and Vegetable Incentive Programs.

The purpose of this communication is to describe the preliminary evaluation of the Virginia Fresh Match (VFM) financial incentive program for fresh fruits and vegetables for Virginia Supplemental Nutrition Assistance Program shoppers and to determine if there were differences in incentive outcomes by race. In this cross-sectional study, a questionnaire was administered to shoppers using Virginia Fresh Match incentives at participating farmers markets and community-based food retail outlets. Repeated measures ANOVAs were used to detect differences in fruit and vegetable consumption between demographic groups over time. Chi-square tests were used to determine if there were associations between race and perceived impact of VFM incentives on making food last and the attribution of VFM incentives to changes in fruit and vegetable consumption frequency. Frequency of fruit and vegetable intake was significantly higher during VFM incentive use, with a difference of 1.17 ± 0.07 and 1.07 ± 0.07 on a Likert scale measure, respectively (p ≤ 0.001). There were racial differences in assertions that VFM incentives helped food to last. VFM incentives were effective at increasing fruit and vegetable consumption, but racial differences should be considered in the administration of VFM to avoid reinforcing systems or approaches that may contribute to disparities in food access and food security.