ABSTRACT
The possibility to overcome the standard quantum limit (SQL) by engineering specific quantum correlations between the atoms is attracting increasing interest in the field of atom interferometry. Recently, Bose-Einstein condensates (BECs) have been pinpointed as optimal candidates for the realization of entanglement-enhanced atom interferometers with spatially separated arms either in trapped [1] or free-fall [2] configurations. However, either due to the presence of residual interactions during the interferometer sequence or due to the fast expansion of the BEC during the state preparation, only a modest sub-SQL sensitivity gain is predicted.
To overcome these problems, we recently proposed a novel method we refer to as Delta-Kick Squeezing (DKS) [3]. This method involves the rapid action of an external trap focusing the matter-waves to significantly increase the atomic densities during a preparation stage. This method is explored in the two relevant cases of Raman or Bragg scattering light pulses. In the second case, we demonstrated the possibility to implement a non-linear readout scheme making the sub-SQL sensitivity highly robust against imperfect atom counting detection [4,5]. We predict more than 30 dB of sensitivity gain beyond the SQL, assuming realistic parameters and millions of atoms in the BEC.
References:
[1] R. Corgier, L.Pezzè and A. Smerzi, PRA 103 (2021).
Nonlinear Bragg interferometer with a trapped Bose-Einstein condensate
[2] S. S. Szigeti, S. P. Nolan, J. D. Close, and S. A. Haine, PRL 125 (2020).
High Precision quantum-enhanced gravimetry with a Bose-Einstein condensate
[3] R. Corgier, N. Gaaloul, A. Smerzi and L.Pezzè, PRL 127 (2021).
Delta-kick Squeeing
[4] E. Davis, G. Bentsen, and M. Schleier-Smith, PRL 116, 053601 (2016).
Approaching the Heisenberg limit without single-particle detection.
[5] O. Hosten, R. Krishnakumar, N. J. Engelsen, and M. A. Kasevich, Science 352 (2016).
Quantum phase magnification