Generation of nonclassical photon pairs for scalable quantum communication with atomic ensembles

Kuzmich, A.; Bowen, Warwick P.; Boozer, A. D.; Boca, A.; Chou, C. W.; Duan, L.-M.; Kimble, H. J.

doi:10.1038/nature01714

Cited by 680 publications

(668 citation statements)

References 28 publications

(49 reference statements)

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“…Finally, a strong red pulse is used to read out the phonon state via emission of an anti-Stokes scattered photon [30]. We confirm the non-classical photon-phonon correlations on the basis of an observed violation of a Cauchy-Schwarz inequality for the cross-correlation of the coincidence measurements between the Stokes and antiStokes photons [3].Precooling of the nanomechanical device is performed using a dilution refrigerator that operates at a base temperature of approximately 25 mK. If the mechanical system is in its quantum ground state of motion, then anti-Stokes processes cannot occur because no additional phonons can be extracted to support the scattering.…”

supporting

confidence: 58%

“…A detailed derivation of the CauchySchwarz inequality for the case of non-stationary fields, as are being used here, is provided in ref. [3].We find a clear violation for an extended regime of time delays. Figure 3b shows the value of g om at a time delay of 100 ns.…”

mentioning

confidence: 65%

“…P (W ∩R) is the probability for a joint detection of both a Stokes (W , 'write') and an anti-Stokes (R, 'read') photon from these pulses, and P (W ) and P (R) are the unconditional probabilities to detect either of the two photons. For all pair correlations of classical origin, the value of g (2) om is bounded by a Cauchy-Schwarz inequality of the form [3] g (2) om (0, δt) ≤ g (2) oo,δt (0)g (2) mm,δt (0)…”

Section: 7% (See Methods)mentioning

confidence: 99%

“…A violation of this inequality [3,31,32] is an unambiguous measure for the non-classicality of the generated photon-phonon state. The Cauchy-Schwarz inequality for coincidence detection marks a well-defined border between the quantum and classical domain.…”

Section: 7% (See Methods)mentioning

confidence: 99%

“…We define the normalized second-order correlation function for two, not necessarily different modes α and β, and the respective annihilation operatorsâ α andâ β , to be (references [3,42] and references therein)…”

Section: Mechanical Response To Optical Pulsesmentioning

confidence: 99%

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Non-classical correlations between single photons and phonons from a mechanical oscillator

Riedinger

Hong

Norte

et al. 2016

Nature

455

437

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Interfacing a single photon with another quantum system is a key capability in modern quantum information science. It allows quantum states of matter, such as spin states of atoms [1,2], atomic ensembles [3,4] or solids [5], to be prepared and manipulated by photon counting and, in particular, to be distributed over long distances. Such light-matter interfaces have become crucial to fundamental tests of quantum physics [6] and realizations of quantum networks [7]. Here we report non-classical correlations between single photons and phonons -the quanta of mechanical motion -from a nanomechanical resonator. We implement a full quantu protocol involving initialization of the resonator in its quantum ground state of motion and subsequent generation and read-out of correlated photon-phonon pairs. The observed violation of a Cauchy-Schwarz inequality is clear evidence for the non-classical nature of the mechanical state generated. Our results demonstrate the availability of on-chip solid-state mechanical resonators as light-matter quantum interfaces. The performance we achieved will enable studies of macroscopic quantum phenomena [8] as well as applications in quantum communication [9], as quantum memories [10] and as quantum transducers [11,12].Over the past few years, nanomechanical devices have been discussed as possible building blocks for quantum information architectures [9,13]. Their unique feature is that they combine an engineerable solid-state platform on the nanoscale with the possibility to coherently interact with a variety of physical quantum systems including electronic or nuclear spins, single charges, and photons [14,15]. This feature enables mechanics-based hybrid quantum systems that interconnect different, independent physical qubits through mechanical modes.A successful implementation of such quantum transducers requires the ability to create and control quantum states of mechanical motion. The first step -the initialization of micro-and nanomechanical systems in their quantum ground state of motion -has been realized in various mechanical systems either through direct cryogenic cooling [16,17] or laser cooling using microwave [18] and optical cavity fields [19]. Further progress in quantum state control has mainly been limited to the domain of electromechanical devices, in which mechanical motion couples to superconducting circuits in the form of qubits and microwave cavities [15]. Recent achievements include single-phonon control of a micromechanical resonator by a superconducting flux qubit [16], the generation of quantum entanglement between quadratures of a microwave cavity field and micromechanical motion [20], * This work was published in Nature 530, 313-316 (2016 Interfacing mechanics with optical photons in the quantum regime is highly desirable because it adds important features such as the ability to transfer mechanical excitations over long distances [9,24]. In addition, the available toolbox of single-photon generation and detection allows for remote quantum state control [7]. However...

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supporting

confidence: 58%

mentioning

confidence: 65%