All Publications


  • Retrieval of cavity-generated atomic spin squeezing after free-space release PHYSICAL REVIEW A Wu, Y., Krishnakumar, R., Martinez-Rincon, J., Malia, B. K., Hosten, O., Kasevich, M. A. 2020; 102 (1)
  • Free Space Ramsey Spectroscopy in Rubidium with Noise below the Quantum Projection Limit PHYSICAL REVIEW LETTERS Malia, B. K., Martinez-Rincon, J., Wu, Y., Hosten, O., Kasevich, M. A. 2020; 125 (4)
  • Free Space Ramsey Spectroscopy in Rubidium with Noise below the Quantum Projection Limit. Physical review letters Malia, B. K., Martínez-Rincón, J. n., Wu, Y. n., Hosten, O. n., Kasevich, M. A. 2020; 125 (4): 043202

    Abstract

    We demonstrate the utility of optical cavity generated spin-squeezed states in free space atomic fountain clocks in ensembles of 390 000 ^{87}Rb atoms. Fluorescence imaging, correlated to an initial quantum nondemolition measurement, is used for population spectroscopy after the atoms are released from a confining lattice. For a free fall time of 4 milliseconds, we resolve a single-shot phase sensitivity of 814(61) microradians, which is 5.8(0.6) decibels (dB) below the quantum projection limit. We observe that this squeezing is preserved as the cloud expands to a roughly 200  μm radius and falls roughly 300  μm in free space. Ramsey spectroscopy with 240 000 atoms at a 3.6 ms Ramsey time results in a single-shot fractional frequency stability of 8.4(0.2)×10^{-12}, 3.8(0.2) dB below the quantum projection limit. The sensitivity and stability are limited by the technical noise in the fluorescence detection protocol and the microwave system, respectively.

    View details for DOI 10.1103/PhysRevLett.125.043202

    View details for PubMedID 32794788