Retrieval of cavity-generated atomic spin squeezing after free-space release

Abstract

We demonstrate that releasing atoms into free space from an optical lattice does not deteriorate cavitygenerated spin squeezing for metrological purposes. In this work, an ensemble of 500 000 spin-squeezed atoms in a high-finesse optical cavity with near-uniform atom-cavity coupling is prepared, released into free space, recaptured in the cavity, and probed. Up to ∼10 dB of metrologically relevant squeezing is retrieved for 700 μs free-fall times, and decaying levels of squeezing are realized for up to 3 ms free-fall times. The degradation of squeezing results from loss of atom-cavity coupling homogeneity between the initial squeezed state generation and final collective state readout. A theoretical model is developed to quantify this degradation and this model is experimentally validated.

Collective-Mode Enhanced Matter-Wave Optics

“…Our method might be of interest in this context. Delta-kicks start to be explored in squeezing experiments [43,44] and can be an interesting addition to other squeezing schemes [45]. Furthermore, such spin-polarized, dilute and slowly expanding gases are important for metrology [46,47] as well as quantum gas experiments in drop towers [7,26], fountains [10] and space, as envisioned by the ISS space mission BECCAL [48].…”

Utilizing machine learning to improve the precision of fluorescence imaging of cavity-generated spin squeezed states

“…The collection inhomogeneity across the cloud can also lead to a degradation in the correlation between a single image and its corresponding QND measurement [15]. In this work, the estimated increase in variance due to this noise source is 0.5% [16], which is negligible. The ML model demonstrated here primarily reduces the variance from shot-to-shot fluctuations in the atom cloud distributions coupled with the detection inhomogeneity.…”

Large cooperativity in strongly coupled chip-scale photonic-atomic integrated system

“…However, starting from the 1980s 38 the technological advancement both in the fabrication process of optical cavities and in laser light sources has allowed scientists to reach the strong coupling regime, where the dissipation rate of the system is lower than the spontaneous emission rate and a coherent interchange of energy can be maintained. This has opened the door for numerous research groups to study the strongly coupled cavityatom interaction of a single atom [39][40][41] , an ensemble of cold atoms [42][43][44] , and up to millions of hot atoms [45][46][47] . These experiments, although substantial in their scientific contribution, have not scaled down to the micron sized cavity regime.…”