Journal of East China Normal University(Natural Science) ›› 2022, Vol. 2022 ›› Issue (4): 154-162.doi: 10.3969/j.issn.1000-5641.2022.04.016

• Physics and Electronics • Previous Articles    

Quantum nondemolition measuremen generated spin-squeezed Bose-Einstein condensate confined in a double-well trap

Yangxu JI1, Ebubechukwu O. ILO-OKEKE2, Tim BYRNES1,2,*()   

  1. 1. State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
    2. Department of Physics, New York University Shanghai, Shanghai 200122, China
  • Received:2021-08-23 Online:2022-07-25 Published:2022-07-19
  • Contact: Tim BYRNES


This paper studies the use of quantum nondemolition (QND) measurement to produce a spin squeezed atomic Bose-Einstein condensate (BEC) in a double-well trap. The spin squeezed atomic Bose-Einstein condensate is performed by putting the BECs of a double well in the two arms of a Mach Zehnder interferometer and performing a QND measurement. The dynamics of the light-atom system are solved using an exact wave-function approach, in contrast to previous approaches where approximations were made using techniques like the Holstein-Primakoff approximation. The backaction of the measurement on atoms is minimized by monitoring the condensate at zero detection current and the identical coherent beams. At the weak atom-light interaction limit, we find that the average spin direction is relatively unaffected by observing the conditional probability distribution and the Q function distribution. The spin variance is squeezed along the axis of optical coupling.

Key words: Bose-Einstein condensate (BEC), quantum nondemolition (QND) measurement, spin coherent state, Q function

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