Atom-chip-based generation of entanglement for quantum metrology

By M. Riedel, P. Boehi, Yun Li, T. Hänsch, A. Sinatra, Philipp Treutlein. Nature, 2010

713 citations recorded by the source corpus.

Atom chips provide a versatile quantum laboratory for experiments with ultracold atomic gases. They have been used in diverse experiments involving low-dimensional quantum gases, cavity quantum electrodynamics, atom–surface interactions, and chip-based atomic clocks and interferometers. However, a severe limitation of atom chips is that techniques to control atomic interactions and to generate entanglement have not been experimentally available so far. Such techniques enable chip-based studies of entangled many-body systems and are a key prerequisite for atom chip applications in quantum simulations, quantum information processing and quantum metrology. Here we report the experimental generation of multi-particle entanglement on an atom chip by controlling elastic collisional interactions with a state-dependent potential. We use this technique to generate spin-squeezed states of a two-component Bose–Einstein condensate; such states are a useful resource for quantum metrology. The observed reduction in spin noise of -3.7 ± 0.4 dB, combined with the spin coherence, implies four-partite entanglement between the condensate atoms; this could be used to improve an interferometric measurement by -2.5 ± 0.6 dB over the standard quantum limit. Our data show good agreement with a dynamical multi-mode simulation and allow us to reconstruct the Wigner function of the spin-squeezed condensate. The techniques reported here could be directly applied to chip-based atomic clocks, currently under development.

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

View Paper: https://www.semanticscholar.org/paper/af9381879cd231556f8cae890079f3c4f6140aac

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Citations in the corpus

Macroscopic quantum states: Measures, fragility, and implementations (2017, methodology): “Recently, the techniques reported in Riedel et al. (2010) have been used to prove that the internal correlations between 480 atoms in a spin-squeezed states are strong enough to violate a Bell inequality (Schmied et al., 2016).”
Quantum-enhanced measurements without entanglement (2017, background): “So far the best experimentally demonstrated approximations to Fock states with massive bosons are number-squeezed states with a few dB of squeezing (Esteve et al., 2008; Gross et al., 2010b; Riedel et al., 2010b).”
Quantum metrology with nonclassical states of atomic ensembles (2016, methodology): “Spin squeezing obtained via one-axis twisting dynamics in a Bose-Einstein condensate has been first experimentally demonstrated by Gross et al. (2010) and Riedel et al. (2010).”
Spin squeezing, entanglement and quantum metrology with Bose–Einstein condensates (2012, methodology): “[84] Riedel M F, Böhi P, Li Y, Hänsch T W, Sinatra A, and Treutlein P 2010 Atom-chip-based generation of entanglement for quantum metrology.”
Colloquium: Nonequilibrium dynamics of closed interacting quantum systems (2010, background): “From a technological perspective, there is an increasing thrust towards engineering ultracold atomic many-body systems for applications in quantum metrology (Appel et al., 2009; Estéve et al., 2008; Leroux et al., 2010; Meiser et al., 2008; Riedel et al., 2010; Vengalattore et al., 2007).”
Spin-nematic squeezed vacuum in a quantum gas (2011, methodology): “Here we prefer an analysis using the commutators of the SU(3) group describing the spin-1 system, as it provides more insight.”
Quantum spin squeezing (2010, background): “The particle collisions induced decoherence in the generation of spin squeezing was studied in [151], and spin-squeezed states generated in BEC are robust to dissipation [152], and particle losses [126, 153, 154].”
Spinor Bose gases: Symmetries, magnetism, and quantum dynamics (2013, background): “…of the vector spin for gases of spin-1/2 atoms (Takano et al., 2009) and also higher-spin atoms (Kuzmich et al., 1998, 2000), and for pseudo-spin-1/2 systems (Appel et al., 2009; Esteve et al., 2008; Gross et al., 2010; Hammerer et al., 2010; Riedel et al., 2010; SchleierSmith et al., 2010).”