Strongly coupling a cavity to inhomogeneous ensembles of emitters: Potential for long-lived solid-state quantum memories

Diniz, Igor; Portolan, S.; Ferreira, Robson; Gérard, Jean‐Michel; Bertet, Patrice; Auffèves, Alexia

doi:10.1103/physreva.84.063810

Cited by 165 publications

(193 citation statements)

References 24 publications

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“…These results are consistent with the sharp falloff of the inhomogeneously broadened spectra where the coherence of the inhomogeneously broadened dipoles is maintained 35 . This is in keeping with the narrow polariton linewidths observed and with the observations of Gambino et al 24 .…”

Section: A Single Organic Microcavitysupporting

confidence: 87%

Coupling of exciton-polaritons inlow−Qcoupled microcavities beyond the rotating wave approximation

et al. 2015

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We have demonstrated coupling between a pair of ultrastrong light-matter coupled microcavities composed of neat glassy organic dye films between metallic (silver) mirrors at room temperature. Based upon our modified coupled oscillator model, we have observed that the degeneracy between the Rabi splittings associated with the symmetric and antisymmetric cavity modes is broken by the higher-order anti-resonant terms in the Hamiltonian associated with the breakdown of the rotating wave approximation in the ultrastrong coupling regime. These results are in quantitative agreement with both experiment and transfer matrix modeling. The component cavities are characterized by Q factors around 12 and display a large vacuum Rabi splitting around 1.12 eV between the upper and lower polariton branches, which is about 52% of the excited state energy, thus indicating ultrastrong coupling in each individual cavity. This large splitting is due to the large oscillator strength of the neat dye glass. We have also observed large polariton-induced incidence-side asymmetry in reflection spectra in a coupled cavity pair with one cavity having no exciton.

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Section: A Single Organic Microcavitysupporting

confidence: 87%

Coupling of exciton-polaritons inlow−Qcoupled microcavities beyond the rotating wave approximation

et al. 2015

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“…Mat. and [20,25,26] that in both curves shown in Fig. 2b P e (τ ) tends towards 0.08 at long times, as is also found with the qubit initially in |g .…”

supporting

confidence: 73%

“…We demonstrate that this process preserves quantum coherence by performing quantum state tomography of the qubit. These results constitute a first proof of concept of spin-ensemble based quantum memory for superconducting qubits [10][11][12]. As a landmark of the successful marriage between a superconducting qubit and electronic spins, we detect with the qubit the hyperfine structure of the NV center.…”

mentioning

confidence: 87%

Hybrid Quantum Circuit with a Superconducting Qubit Coupled to a Spin Ensemble

et al. 2011

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Present-day implementations of quantum information processing rely on two widely different types of quantum bits (qubits). On the one hand, microscopic systems such as atoms or spins are naturally well decoupled from their environment and as such can reach extremely long coherence times [1,2]; on the other hand, more macroscopic objects such as superconducting circuits are strongly coupled to electromagnetic fields, making them easy to entangle [3,4] although with shorter coherence times [5,6]. It thus seems appealing to combine the two types of systems in hybrid structures that could possibly take the best of both worlds. Here we report the first experimental realization of a hybrid quantum circuit in which a superconducting qubit of the transmon type [5,7] is coherently coupled to a spin ensemble consisting of nitrogen-vacancy (NV) centers in a diamond crystal [8] via a frequency-tunable superconducting resonator [9] acting as a quantum bus. Using this circuit, we prepare arbitrary superpositions of the qubit states that we store into collective excitations of the spin ensemble and retrieve back later on into the qubit. We demonstrate that this process preserves quantum coherence by performing quantum state tomography of the qubit. These results constitute a first proof of concept of spin-ensemble based quantum memory for superconducting qubits [10][11][12]. As a landmark of the successful marriage between a superconducting qubit and electronic spins, we detect with the qubit the hyperfine structure of the NV center.Superconducting qubits have been successfully coupled to electromagnetic [13] as well as mechanical [14] resonators; but coupling them to microscopic systems in a controlled way has up to now remained an elusive perspective -even though qubits sometimes turn out to be coupled to unknown and uncontrolled microscopic degrees of freedom with relatively short coherence times [15]. Whereas the coupling constant g of one individual microscopic system to a superconducting circuit is usually too weak for quantum information applications, ensembles of N such systems are coupled with a constant g √ N enhanced by collective effects.This makes possible to reach a regime of strong coupling between one collective variable of the ensemble and the circuit. This collective variable, which behaves in the low excitation limit as a harmonic oscillator, has been proposed [10-12] as a quantum memory for storing the state of superconducting qubits. Experimentally, the strong coupling between an ensemble of electronic spins and a superconducting resonator has been demonstrated 2 spectroscopically [16][17][18], and the storage of a microwave field into collective excitations of a spin ensemble has been observed very recently [19,20]. These experiments were however carried out in a classical regime since the resonator and spin ensemble behaved as two coupled harmonic oscillators driven by large microwave fields. In the perspective of building a quantum memory, it is instead necessary to perform experiments at the level of a...

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“…The coherence performance of the spin ensemble is affected not only by the width of the inhomogeneous broadening but also by its shape. 41,42 By choosing an appropriate type of distribution of the inhomogeneous broadening of spins, such as a Gaussian distribution, the decoherence would be dominated by the spins' homogeneous broadening. This effect, known as cavity protection, could provide longer coherence times in our proposed circuit.…”

Section: Strong-coupling Regimementioning

confidence: 99%

Hybrid quantum circuit consisting of a superconducting flux qubit coupled to a spin ensemble and a transmission-line resonator

Xiang

Lü

et al. 2013

Phys. Rev. B

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We propose an experimentally realizable hybrid quantum circuit for achieving a strong coupling between a spin ensemble and a transmission-line resonator via a superconducting flux qubit used as a data bus. The resulting coupling can be used to transfer quantum information between the spin ensemble and the resonator. In particular, in contrast to the direct coupling without a data bus, our approach requires far less spins to achieve a strong coupling between the spin ensemble and the resonator (e.g., three to four orders of magnitude less). This proposed hybrid quantum circuit could enable a long-time quantum memory when storing information in the spin ensemble, and allows the possibility to explore nonlinear effects in the ultrastrong-coupling regime.

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Strongly coupling a cavity to inhomogeneous ensembles of emitters: Potential for long-lived solid-state quantum memories

Cited by 165 publications

References 24 publications

Coupling of exciton-polaritons inlow−Qcoupled microcavities beyond the rotating wave approximation

Coupling of exciton-polaritons inlow−Qcoupled microcavities beyond the rotating wave approximation

Hybrid Quantum Circuit with a Superconducting Qubit Coupled to a Spin Ensemble

Hybrid quantum circuit consisting of a superconducting flux qubit coupled to a spin ensemble and a transmission-line resonator

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