Comparative model study of two-photon deterministic passive quantum logical gates

Gea‐Banacloche, Julio; Pedrotti, Leno S.

doi:10.1103/physreva.83.042333

Cited by 11 publications

(27 citation statements)

References 22 publications

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“…To have φ = π/4, Koshino, Ishizaka and Nakamura derived the condition δ a = 2g 2 /κ for the detuning between the atom and the cavity, assuming implicitly that the cavity and the field were resonant. For the more general case where the field is detuned from the cavity resonance by an amount ∆, we showed in [14] that the condition to have φ = π/4 is…”

Section: The Original Kin Schemementioning

confidence: 99%

Single-photon, cavity-mediated gates: Detuning, losses, and nonadiabatic effects

Gea‐Banacloche

Pedrotti

2012

Phys. Rev. A

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We study several extensions of the single-photon, cavity-mediated quantum logical gates recently proposed by Koshino, Ishizaka and Nakamura: to a double-sided cavity configuration, to the case where the two atomic ground states are nondegenerate, and to the non-adiabatic regime. Our analysis can be used to estimate the effects of various imperfections, and to prepare the way for a proof-of-principle demonstration with present technology. We are able to present a full solution for the outgoing pulses, in the frequency domain, which is valid for arbitrary incident pulses and cavity parameters. From this we find, among other results, that the leading correction to the adiabatic approximation can be made to vanish for a suitable choice of detunings, provided the cavity is "good enough" (high enough ratio of coupling to loss). This could significantly relax the need for long single-photon pulses in this scheme.

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Section: The Original Kin Schemementioning

confidence: 99%

Single-photon, cavity-mediated gates: Detuning, losses, and nonadiabatic effects

Gea‐Banacloche

Pedrotti

2012

Phys. Rev. A

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“…By using a -type three-level system as an emitter in waveguide QED, we can enhance the probability that the input photon induces the Raman transition and accordingly switches the quantum state of the system. In particular, it has been theoretically revealed that this probability may reach unity when the following conditions are satisfied: (i) the system is coupled to the waveguide field in reflection geometry; and (ii) the two radiative decay rates from the top level of the system are identical [23][24][25][26][27][28]. Then, the input photons are never reflected coherently and the amplitude of the reflected wave vanishes accordingly.…”

Section: Introductionmentioning

confidence: 99%

“…We refer to this phenomenon as the impedance matching by a system, in analogy with properly terminated electric circuits. Such impedance-matched systems are attractive for quantum information processing, since the expected deterministic quantum dynamics is applicable to quantum memories [24][25][26], single-photon transistors [27,28], photon sorters [29], photon-photon gates [24-26, 30, 31] and single-photon detectors in microwave domain [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Theory of deterministic down-conversion of single photons occurring at an impedance-matched Λ system

et al. 2013

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We theoretically investigate the optical response of a system interacting with a semi-infinite waveguide field. In particular, we focus on the case of an impedance-matched system, in which the two decay rates from the top level are identical. We derive the analytical formulae to evaluate the amplitude and the power spectrum of the output field, and present numerical results assuming an implementation by a circuit quantum electrodynamics system. For a low input power (single-photon regime), input photons are downconverted deterministically by inducing the Raman transition in the system. In contrast, for a high input power (multi-photon regime), the conversion efficiency decreases because of the saturation of the system.

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“…The charm of such impedance-matched systems is the deterministic electronic dynamics induced by single photons, which enables novel quantum technologies. Based on such Λ systems, single-photon transistors, quantum memories, and optical quantum gates have been theoretically proposed [11][12][13][14][15][16].In superconducting qubits, we use several discrete levels formed at the bottom of the anharmonic potential as an artificial atom. We usually make the potential symmetric in order to suppress dephasing.…”

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Implementation of an Impedance-MatchedΛSystem by Dressed-State Engineering

et al. 2013

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In one-dimensional optical setups, light-matter interaction is drastically enhanced by the interference between the incident and scattered fields. Particularly, in the impedance-matched Λ-type three-level systems, a single photon deterministically induces the Raman transition and switches the electronic state of the system. Here we show that such a Λ system can be implemented by using dressed states of a driven superconducting qubit and a resonator. The input microwave photons are perfectly absorbed and are down-converted into other frequency modes in the same waveguide. The proposed setup is applicable to single-photon detection in the microwave domain.PACS numbers: 03.67. Lx, 85.25.Cp, 42.50.Pq In one-dimensional optical setups, radiation from a quantum emitter is guided completely to specified onedimensional propagating modes. We can realize such setups in a variety of physical systems, such as optical cavity quantum electrodynamics (QED) systems using atoms or quantum dots [1][2][3] and circuit QED systems using superconducting qubits [4][5][6]. When we apply a field to excite the emitter through the one-dimensional mode in these setups, the incident field inevitably interferes with the field scattered by the emitter due to the low dimensionality [7]. As a result, we can realize unique optical phenomena that are not achievable in three-dimensional free space. A classical example is the complete transmission of a resonant field through a two-sided cavity, in which reflection from the cavity is forbidden due to the destructive interference between the incident field and the cavity emission in the reflection direction. Such one-dimensional optical setups in which reflection from the emitter is forbidden are called impedance-matched, in analogy with properly terminated electric circuits [8,9]. Recently, perfect reflection of the incident field by a single emitter has been confirmed in both optical cavity QED and circuit QED systems [2,4]. Here, transmission is forbidden by the destructive interference occurring in the transmission direction.In this study, we investigate a three-level Λ system interacting with a semi-infinite one-dimensional field in a reflection geometry (Fig. 1). We denote the three levels of the Λ system by |g , |m and |e from the lowest. We assume that |m decays to |g with a finite lifetime and therefore that the system is in |g when stationary. When a single photon resonant to the |g → |e transition is input, there are three possible processes: (a) simple reflection without exciting the system, (b) elastic scattering, inducing the |g → |e → |g transitions, and (c) inelastic scattering, inducing the |g → |e → |m → |g transitions. Destructive interference occurs here between processes (a) and (b). In particular, they cancel each other completely when the two decay rates from the top level |e are identical (Γ eg = Γ em ) and the coherence length of the input photon is sufficiently long. As a result, the input photon is down-converted deterministically, inducing the Raman transition in the sy...

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Comparative model study of two-photon deterministic passive quantum logical gates

Cited by 11 publications

References 22 publications

Single-photon, cavity-mediated gates: Detuning, losses, and nonadiabatic effects

Single-photon, cavity-mediated gates: Detuning, losses, and nonadiabatic effects

Theory of deterministic down-conversion of single photons occurring at an impedance-matched Λ system

Implementation of an Impedance-MatchedΛSystem by Dressed-State Engineering

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