Spin-nematic squeezed vacuum in a quantum gas

By C. Hamley, C. Gerving, T. Hoang, E. Bookjans, M. Chapman. Nature Physics, 2011

270 citations recorded by the source corpus.

Squeezed states—which permit precision beyond the scope of Heisenberg’s uncertainty relation—are well established for spin-1/2 particles. Now an elegant demonstration of squeezing in spin-1 condensates generalizes the criteria for squeezed states to higher spin dimensions. The standard quantum limit of measurement uncertainty can be surpassed using squeezed states, which minimize the uncertainty product in Heisenberg’s relation by reducing the uncertainty of one property at the expense of another1. Collisions in ultracold atomic gases have been used to induce quadrature spin squeezing in two-component Bose condensates 2,3, for which the complementary properties are the components of the total spin vector. Here, we generalize this finding to a higher-dimensional spin space by measuring squeezing in a spin-1 Bose condensate. Following a quench through a quantum phase transition, we demonstrate that spin-nematic quadrature squeezing improves on the standard quantum limit by up to 8–10 dB—a significant increase on previous measurements. This squeezing is associated with negligible occupation of the squeezed modes, and is analogous to optical two-mode vacuum squeezing. The observation has implications for continuous variable quantum information and quantum-enhanced magnetometry.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/d9a20a98221e96f6f3ad42492ef3bc9e0edf0f6d

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Citations in the corpus

Spinor Bose gases: Symmetries, magnetism, and quantum dynamics (2013, background): “…measurement uncertainty, i.e. with an imprecision ∆N < N1/2 for measurements on N atoms, has been achieved by several groups (Bookjans et al., 2011a; Gross et al., 2011; Hamley et al., 2012; Lücke et al., 2011) to probe correlations predicted from solutions for the many-body spin Hamiltonian (Sec.”
Quantum metrology with nonclassical states of atomic ensembles (2016, methodology): “The mean-field limit of 14 Some authors have also studied spin-1 condensates using the a quadrupole tensor operator Q̂ (Hamley et al., 2012; Müstecaplıoğlu et al., 2002; Sau et al., 2010) with components related to Eq.”
Entanglement certification from theory to experiment (2018, methodology): “Note that other collective su(2j+1) operators, and thus correspondingly different collective Bloch spheres, have also been recently considered in spinor ensembles [301, 302].”