Quantum communication and computing with atomic ensembles using a light-shift-imbalance-induced blockade

Shahriar, M. S.; Pati, G. S.; Salit, K.

doi:10.1103/physreva.75.022323

Cited by 21 publications

(24 citation statements)

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“…Moreover, the ideal performance is achieved when T = 0 K and γ 0 → 0, in which case, we 79) and therefore,…”

Section: Parity-gate Fidelity Analysismentioning

confidence: 62%

“…There is a new blockade mechanism by which we can prevent the atomic ensemble from absorbing more than one excitation, thus treat the atomic ensemble as a two-level atom. This is based on the light-shift imbalance in a Raman transition [78], and it has been proposed for realizing quantum communication and computation systems with atomic ensembles [79]. It would be interesting to employ the techniques that we learned in Chapters 2 and 4 to analyze these systems.…”

Section: Future Workmentioning

confidence: 99%

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Long-distance quantum communication with neutral atoms

Razavi

Shapiro

2006

Phys. Rev. A

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In this thesis, we develop quantitative performance analyses for a variety of quantum communication/computation systems that have the common feature of employing neutral atoms for storage/processing and photons for qubit transmission. For most of these systems, there is a lack of a precise performance analysis to enable a comparison between different scenarios from a top-level system standpoint. One main goal of this thesis is to fill that gap, thus providing quantum system designers with realistic estimates of system performance that can guide and inform the design process.For many applications in quantum communication and distributed quantum processing, we need to share, in advance, an entangled state between two parties. Thus, entanglement distribution is at the core of long-distance quantum communication systems. It not only includes generation and transmission of entangled states, but it also requires storing them for further processing purposes. Whereas the photons are the prime candidate for the former task, they are not appropriate for long-time storage and processing. Metastable levels in some alkali atoms, e.g., rubidium, are attractive venues for quantum storage. In this thesis, we study several basic quantum memory modules-all based on single trapped atoms in high-finesse optical cavities-and analytically evaluate how efficiently they can be loaded with (entangled) quantum states. We propose a non-adiabatic mechanism for driving offresonant Raman transitions that can be used in loading trapped-atom quantum memories. Our method is more flexible than its adiabatic counterpart in that it allows use of larger cavities and a larger class of driving sources.We also describe two proposed implementations for long-distance quantum communication-one that uses trapped atoms as quantum memories and another that employs atomic ensembles for quantum storage. We provide, for the first time, a detailed quantitative performance analysis of the latter system, which enables us to compare these two systems in terms of the fidelity and the throughput that they achieve for entanglement distribution, repeater operation, and quantum teleportation.Finally, we study quantum computing systems that use the cross-Kerr nonlinearity between single-photon qubits and a coherent mode of light. The coherent beam serves a mediating role in coupling two weak single-photon beams. We analytically study this structure using a continuous-time formalism for the cross-Kerr effect in optical fibers. Our results establish stringent conditions that must be fulfilled for the system's proper operation.

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“…Moreover, the ideal performance is achieved when T = 0 K and γ 0 → 0, in which case, we 79) and therefore,…”

Section: Parity-gate Fidelity Analysismentioning

confidence: 62%

Section: Future Workmentioning

confidence: 99%

Long-distance quantum communication with neutral atoms

Razavi

Shapiro

2006

Phys. Rev. A

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“…Here we will restrict ourselves to a very brief overview. One class of proposals keeps atomic ensembles and linear optical processing as important ingredients, but supplements them with additional non-linear elements such as the Kerr effect (He et al, 2008) or light shift induced blockade (Shahriar et al, 2007).…”

Section: Other Approaches Towards Quantum Repeatersmentioning

confidence: 99%

Quantum repeaters based on atomic ensembles and linear optics

et al. 2011

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The distribution of quantum states over long distances is limited by photon loss. Straightforward amplification as in classical telecommunications is not an option in quantum communication because of the no-cloning theorem. This problem could be overcome by implementing quantum repeater protocols, which create long-distance entanglement from shorter-distance entanglement via entanglement swapping. Such protocols require the capacity to create entanglement in a heralded fashion, to store it in quantum memories, and to swap it. One attractive general strategy for realizing quantum repeaters is based on the use of atomic ensembles as quantum memories, in combination with linear optical techniques and photon counting to perform all required operations. Here we review the theoretical and experimental status quo of this very active field. We compare the potential of different approaches quantitatively, with a focus on the most immediate goal of outperforming the direct transmission of photons.

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“…However, they did not indicate concretely how the gyroscope's sensitivity can be enhanced by slow-light technique. After several years, Shahriar et al [17,18] proved that this enhancement cannot be achieved for the case of absolute rotation, in which case slow light medium moves together with the rest of gyroscope. They also proved only the case of relative rotation, in which case there is a relative rotation between the slow light medium and the rest of the gyroscope, can enhance the gyroscope's sensitivity.…”

Section: Introductionmentioning

confidence: 97%