Speaker
Description
The well-known spin squeezing coefficient efficiently quantifies the sensitivity and entanglement of Gaussian states [1,2]. However, this coefficient is insufficient to characterize the much wider class of non-Gaussian quantum states that can generate even larger sensitivity gains. In this talk, we present a non-Gaussian extension of spin squeezing based on reduced variances of nonlinear observables that can be optimized under relevant constraints [3]. We determine the scaling of the sensitivity enhancement that is made accessible from increasingly complex quantum states generated by one-axis-twisting in the presence of relevant noise processes [4,5]. Our analytical results provide recipes for optimal non-Gaussian spin squeezing in atomic experiments.
[1] D. J. Wineland, J. J. Bollinger, W. M. Itano, F. L. Moore, and D. J. Heinzen, Spin squeezing and reduced quantum noise in spectroscopy, Phys. Rev. A 46, R6797 (1992).
[2] L. Pezzè, A. Smerzi, M. K. Oberthaler, R. Schmied, and P. Treutlein, Quantum metrology with nonclassical states of atomic ensembles, Rev. Mod. Phys. 90, 035005 (2018).
[3] M. Gessner, A. Smerzi, and L. Pezzè, Metrological Non-linear Squeezing Parameter, Phys. Rev. Lett. 122, 090503 (2019).
[4] Y. Baamara, A. Sinatra, M. Gessner, Scaling laws for the sensitivity enhancement of non-Gaussian spin states, Phys. Rev. Lett. 127, 160501 (2021).
[5] Y. Baamara, A. Sinatra, M. Gessner, Squeezing of nonlinear spin observables by one axis twisting in the presence of decoherence: An analytical study, Comptes Rendus. Physique 23, 1 (2022).
