Strong atom–field coupling for Bose–Einstein condensates in an optical cavity on a chip

By Y. Colombe, T. Steinmetz, G. Dubois, F. Linke, D. Hunger, J. Reichel. Nature, 2007

596 citations recorded by the source corpus.

An optical cavity enhances the interaction between atoms and light, and the rate of coherent atom–photon coupling can be made larger than all decoherence rates of the system. For single atoms, this ‘strong coupling regime’ of cavity quantum electrodynamics has been the subject of many experimental advances. Efforts have been made to control the coupling rate by trapping the atom and cooling it towards the motional ground state; the latter has been achieved in one dimension so far. For systems of many atoms, the three-dimensional ground state of motion is routinely achieved in atomic Bose–Einstein condensates (BECs). Although experiments combining BECs and optical cavities have been reported recently, coupling BECs to cavities that are in the strong-coupling regime for single atoms has remained an elusive goal. Here we report such an experiment, made possible by combining a fibre-based cavity with atom-chip technology. This enables single-atom cavity quantum electrodynamics experiments with a simplified set-up and realizes the situation of many atoms in a cavity, each of which is identically and strongly coupled to the cavity mode. Moreover, the BEC can be positioned deterministically anywhere within the cavity and localized entirely within a single antinode of the standing-wave cavity field; we demonstrate that this gives rise to a controlled, tunable coupling rate. We study the heating rate caused by a cavity transmission measurement as a function of the coupling rate and find no measurable heating for strongly coupled BECs. The spectrum of the coupled atoms–cavity system, which we map out over a wide range of atom numbers and cavity–atom detunings, shows vacuum Rabi splittings exceeding 20 gigahertz, as well as an unpredicted additional splitting, which we attribute to the atomic hyperfine structure. We anticipate that the system will be suitable as a light–matter quantum interface for quantum information.

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

View Paper: https://www.semanticscholar.org/paper/23cac8b01ea34edda92438571090bc50dabbe78c

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Citations in the corpus

Interaction between Atomic Ensembles and Optical Resonators: Classical Description (2011, background): “Significant effort has gone towards increasing the single-photon Rabi frequency 2g (also called vacuum Rabi frequency), at which a single quantum of excitation is exchanged between the atom and the cavity, above the dissipation rates κ and Γ at which the photon is lost from the cavity or from the…”
Quantum many‐body phenomena in coupled cavity arrays (2008, methodology): “Strong coupling experiments with many atoms in one cavity and at the same time large cooperativity factors for each individual atom have been performed with fibre Fabry-P´ erot cavities [ 64 ].”
Coherent manipulation of Bose–Einstein condensates with state-dependent microwave potentials on an atom chip (2009, methodology): “We envisage that the gate can be realized by combining the microwave potentials demonstrated here with techniques for single atom control [21, 22] based on the recently demonstrated optical fiber cavities on atom chips [23].”
Natural and artificial atoms for quantum computation (2010, unknown): “Acknowledgments 9”
Quantum matter built from nanoscopic lattices of atoms and photons (2018, background): “These included whispering-gallerymode resonators (Vernooy et al., 1998; Aoki et al., 2006; O’Shea et al., 2013; Shomroni et al., 2014) and fiber-based cavities (Colombe et al., 2007; Volz et al., 2011; Kato and Aoki, 2015), which increased cooperativities by an order of magnitude.”
Cavity magnonics (2021, background): “…observed subsequently in single atoms interacting with MW (Meschede et al., 1985) and optical (Thompson et al., 1992) cavities, atomic Bose-Einstein condensates in optical cavities (Colombe et al., 2007), and excitons in quantum dots (QDs) coupled to photonic resonators (Hennessy et al., 2007).”
Observation of quantum-measurement backaction with an ultracold atomic gas (2007, background): “Such a measurement may also be applied to monitor the motion of an ensemble of N atoms that are optically trapped (and which, for our set-up, can be treated as independent to a good approximation) within the resonator mod”
Self-organization of a Bose-Einstein condensate in an optical cavity (2008, background): “The realization of collective effects with material exhibiting wavelike behaviour is within reach since the first strong coupling experiments in the ultracold atom temperature regime have already been reported [6,7,8,9].”
Cavity-based quantum networks with single atoms and optical photons (2014, background): “It has enabled the assembly of cavities with mode volumes on the order of 103 λ3 and a cooperativity of C ' 145 (Colombe et al., 2007).”
Nonequilibrium phase transition in a spin-1 Dicke model (2016, background): “A significant amount of effort has been devoted to study coherent control of atoms by strong atom-photon interactions using various systems including optical cavities [5], atom chips [6], and structured optical waveguides [7].”
Atom-chip-based generation of entanglement for quantum metrology (2010, methodology): “Subsequently, state |0〉 is optically pumped into the F = 2 manifold of the ground state using a F = 1 → F ′ = 2 pumping laser [3] and imaged on the F = 2 → F ′ = 3 transition.”