Squeezed state metrology with Bragg interferometers operating in a cavity

Year: 2019

Authors: Shankar A., Salvi L., Chiofalo ML., Poli N., Holland MJ.

Autors Affiliation: Univ Colorado, JILA, NIST, 440 UCB, Boulder, CO 80309 USA; Univ Colorado, Dept Phys, 440 UCB, Boulder, CO 80309 USA; Univ Firenze, Ist Nazl Fis Nucl, Sez Firenze, Dipartimento Fis & Astron, Via Sansone 1, I-50019 Sesto Fiorentino, Italy; Univ Firenze, Ist Nazl Fis Nucl, Sez Firenze, LENS, Via Sansone 1, I-50019 Sesto Fiorentino, Italy; Univ Pisa, Dipartimento Fisica Enrico Fermi, Largo B Pontecorvo 3, I-56127 Pisa, Italy; Ist Nazl Fis Nucl, Largo B Pontecorvo 3, I-56127 Pisa, Italy; CNR, INO, I-00185 Rome, Italy.

Abstract: Bragg interferometers, operating using pseudospin-1/2 systems composed of two momentum states, have become a mature technology for precision measurements. State-of-the-art Bragg interferometers are rapidly surpassing technical limitations and are soon expected to operate near the projection noise limit set by uncorrelated atoms. Despite the use of large numbers of atoms, their operation is governed by single-atom physics. Motivated by recent proposals and demonstrations of Raman gravimeters in cavities, we propose a scheme to squeeze directly on momentum states for surpassing the projection noise limit in Bragg interferometers. In our modeling, we consider the unique issues that arise when a spin squeezing protocol is applied to momentum pseudospins. Specifically, we study the effects of the momentum width of the atomic cloud and the coupling to momentum states outside the pseudospin manifold, as these atoms interact via a mode of the cavity. We show that appreciable levels of spin squeezing can be demonstrated in suitable parameter regimes in spite of these complications. Using this setting, we show how beyond mean-field techniques developed for spin systems can be adapted to study the dynamics of momentum states of interacting atoms. Our scheme promises to be feasible using current technology and is experimentally attractive because it requires no additional setup beyond what will be required to operate Bragg interferometers in cavities.

Journal/Review: QUANTUM SCIENCE AND TECHNOLOGY

Volume: 4 (4)      Pages from: 45010-1  to: 45010-23

More Information: We would like to thank Baochen Wu, James Thompson, Luca Pezze, Augusto Smerzi, John Cooper, Robert Lewis-Swan, Guglielmo Tino and Vladan Vuletic for useful discussions and constructive comments on the manuscript. AS and MH acknowledge financial support from NSF PFC Grant No. PHY 1734006 and DARPA Extreme Sensing. LS, MLC and NP acknowledge financial support from INFN and the Italian Ministry of Education, University and Research (MIUR) under the Progetto Premiale ’Interferometro Atomic’ and PRIN 2015. NP acknowledges financial support from European Research Council, Grant No. 772126 (TICTOCGRAV). MLCand NP are grateful to JILA for the warm welcome and conducive research environment during the Visiting Fellowship, when part of this work was carried out.
KeyWords: Bragg interferometers; spin squeezing; quantum metrology; cavity QED; phase space methods
DOI: 10.1088/2058-9565/ab455d

Citations: 21
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