Two-Mode Vacuum Squeezing of Spin-Nematic Variables in a Spin-1 Condensate

Squeezed states allow interferometers to surpass the standard quantum limit of the Heisenberg uncertainty principle. Here we study spin-nematic squeezing of a spin-1 condensate following a quench through a nematic-ferromagnetic quantum phase transition. We observe up to -8.3 dB squeezing in the variance of the spin-nematic quadratures. This squeezing is observed for negligible occupation of the squeezed modes and is analogous to optical two-mode vacuum squeezing.\footnote{C.D. Hamley, C.S. Gerving, T.M. Hoang, E.M. Bookjans, and M.S. Chapman, ``Spin-Nematic Squeezed Vacuum in a Quantum Gas,'' To appear in \emph{Nature Phys.}}