Remote Entanglement between a Single Atom and a Bose-Einstein Condensate

Lettner, Matthias; Mücke, Martin; Riedl, Stefan; Vo, Christoph; Hahn, Carolin; Baur, Simon; Bochmann, Jörg; Ritter, Stephan; Dürr, Stephan; Rempe, Gerhard

doi:10.1103/physrevlett.106.210503

Cited by 123 publications

(132 citation statements)

References 26 publications

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“…Distributing entangled states after preparation at a central location is practically challenging since decoherence in distribution channels typically degrades entanglement, e.g., [3,4]. Alternatively, a long-range coupling between remote systems can be engineered by exchanging single quanta, and entanglement can be generated this way, as has been recently demonstrated for atoms, photons, and combinations thereof [5,6].…”

Section: Introductionmentioning

confidence: 99%

Continuous joint measurement and entanglement of qubits in remote cavities

2015

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We present a first principles theoretical analysis of the entanglement of two superconducting qubits in spatially separated microwave cavities by a sequential (cascaded) probe of the two cavities with a coherent mode, that provides a full characterization of both the continuous measurement induced dynamics and the entanglement generation. We use the SLH formalism to derive the full quantum master equation for the coupled qubits and cavities system, within the rotating wave and dispersive approximations, and conditioned equations for the cavity fields. We then develop effective stochastic master equations for the dynamics of the qubit system in both a polaronic reference frame and a reduced representation within the laboratory frame. We compare simulations with and analyze tradeoffs between these two representations, including the onset of a non-Markovian regime for simulations in the reduced representation. We provide conditions for ensuring persistence of entanglement and show that using shaped pulses enables these conditions to be met at all times under general experimental conditions. The resulting entanglement is shown to be robust with respect to measurement imperfections and loss channels. We also study the effects of qubit driving and relaxation dynamics during a weak measurement, as a prelude to modeling measurement-based feedback control in this cascaded system.

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Section: Introductionmentioning

confidence: 99%

Continuous joint measurement and entanglement of qubits in remote cavities

2015

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“…The combination of strong absorption and long ground state hyperfine coherence has allowed storage times of miliseconds and efficiencies higher than 75% to be achieved in these systems [12][13][14][15]. Moreover, schemes for broadband operation with single photons at the GHz level have been proposed [16] and also demonstrated experimentally [17]; single photons emitted by a single atom were stored in a Bose-Einstein condensate of the same species and used to produce entanglement between the two remote systems [18].…”

Section: Introductionmentioning

confidence: 99%

An artificial Rb atom in a semiconductor with lifetime-limited linewidth

et al. 2015

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We report results important for the creation of a best-of-both-worlds quantum hybrid system consisting of a solid-state source of single photons and an atomic ensemble as quantum memory. We generate single photons from a GaAs quantum dot (QD) frequency matched to the Rb D2 transitions and then use the Rb transitions to analyze spectrally the quantum dot photons. We demonstrate lifetime-limited QD linewidths (1.42 GHz) with both resonant and nonresonant excitation. The QD resonance fluorescence in the low power regime is dominated by Rayleigh scattering, a route to match quantum dot and Rb atom linewidths and to shape the temporal wave packet of the QD photons. Noise in the solid-state environment is relatively benign: there is a blinking of the resonance fluorescence at MHz rates but negligible dephasing of the QD excitonic transition. We therefore demonstrate significant progress towards the realization of an ideal solid-state source of single photons at a key wavelength for quantum technologies.

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“…This has spurred great activity in exploring hybrid quantum systems with the objective to devise scalable quantum architectures [31]. In particular, generating nonclassical states in atom-photon-coupled hybrid quantum systems has received significant theoretical and experimental interest [32][33][34][35][36][37][38]. Continuing this quest, we envision two spatially-separated BECs confined inside an optical resonator and explore whether macroscopic entanglement between the two atomic BECs can be generated via the coupling to a common photon mode.…”

Section: Model Systemmentioning

confidence: 99%

Cavity-Assisted Generation of Sustainable Macroscopic Entanglement of Ultracold Gases

Joshi

Larson

2015

Atoms

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Prospects for reaching persistent entanglement between two spatially-separated atomic Bose-Einstein condensates are outlined.The system setup comprises two condensates loaded in an optical lattice, which, in return, is confined within a high-Q optical resonator. The system is driven by an external laser that illuminates the atoms, such that photons can scatter into the cavity. In the superradiant phase, a cavity field is established, and we show that the emerging cavity-mediated interactions between the two condensates is capable of entangling them despite photon losses. This macroscopic atomic entanglement is sustained throughout the time-evolution apart from occasions of sudden deaths/births. Using an auxiliary photon mode and coupling it to a collective quadrature of the two condensates, we demonstrate that the auxiliary mode's squeezing is proportional to the atomic entanglement, and as such, it can serve as a probe field of the macroscopic entanglement.

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Remote Entanglement between a Single Atom and a Bose-Einstein Condensate

Cited by 123 publications

References 26 publications

Continuous joint measurement and entanglement of qubits in remote cavities

Continuous joint measurement and entanglement of qubits in remote cavities

An artificial Rb atom in a semiconductor with lifetime-limited linewidth

Cavity-Assisted Generation of Sustainable Macroscopic Entanglement of Ultracold Gases

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