Dispersive Response of a Disordered Superconducting Quantum Metamaterial

Shapiro, D. S.; Macha, P.; Rubtsov, A. N.; Ustinov, A. V.

doi:10.3390/photonics2020449

Cited by 28 publications

(30 citation statements)

References 20 publications

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“…Superconducting qubits can be integrated with microwave waveguides, while the photon field in these waveguides is quantized. Such systems give rise to the effects of Rabi oscillations [7][8][9][10], quantum feedback [11], and gigahertz photon emission [12], while many-qubit systems form subwavelength quantum metamaterials [13][14][15][16]. The well-known Rabi model [17] is applicable for the description of the qubit-photon quantum system [1].…”

Section: Introductionmentioning

confidence: 99%

Dynamical Lamb effect in a tunable superconducting qubit-cavity system

et al. 2015

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A natural atom placed into a cavity with time-dependent parameters can be parametrically excited due to interaction with the quantized photon mode. One of the channels for this process is the dynamical Lamb effect, induced by a nonadiabatic modulation of the atomic-level Lamb shift. However, in experiments with natural atoms it is quite difficult to isolate this effect from other mechanisms of atom excitation. We point out that a transmission line cavity coupled with a superconducting qubit (an artificial macroscopic atom) provides a unique platform for observation of the dynamical Lamb effect. A key idea is to exploit a dynamically tunable qubit-resonator coupling, which was implemented quite recently. By varying the coupling nonadiabatically, it is possible to parametrically excite a qubit through a nonadiabatic modulation of the Lamb shift, even if the cavity was initially empty. The dynamics of such a coupled system is studied within the Rabi model with a time-dependent coupling constant and beyond the rotating-wave approximation. An efficient method to increase the effect through the periodic and nonadiabatic switching of the qubit-resonator coupling energy is proposed.

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Section: Introductionmentioning

confidence: 99%

Dynamical Lamb effect in a tunable superconducting qubit-cavity system

et al. 2015

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“…Superradiance was also observed recently in a circuit-QED system [15]. There have also been several recent experiments on superconducting quantum metamaterials involving large numbers of qubits or resonators [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 95%

“…The difference between the normal and superradiant cases enters in the coefficients of the different operators in Eq. (16). For example, taking ǫ = 0, in the normal phase, θ = 0 and x 0 = 0, while in the superradiant phase, x 0 is given by Eq.…”

Section: Spectrum In the Absence Of Fluctuationsmentioning

confidence: 99%

Spectrum of the Dicke model in a superconducting qubit-oscillator system

et al. 2019

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We calculate the transmission spectrum of a superconducting circuit realization of the Dicke model and identify spectroscopic features that can serve as signatures of the superradiant phase. In particular, we calculate the resonance frequencies of the system as functions of the bias term, which is usually absent in studies on the Dicke model but is commonly present in superconducting qubit circuits. To avoid over-complicating the proposed circuit, we assume a fixed coupling strength. This situation precludes the possibility of observing signatures of the phase transition by varying the coupling strength across the critical point. We show that the spectrum obtained by varying the bias point under fixed coupling strength can contain signatures of the normal and superradiant phases: in the normal phase one expects to observe two spectral lines, while in the superradiant phase four spectral lines are expected to exist close to the qubits' symmetry point. Provided that parameter fluctuations and decoherence rates are sufficiently small, the four spectral lines should be observable and can serve as a signature of the superradiant phase.

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“…Solid state realizations of qubit ensembles are superconducting Josephson circuits [4,8,9], nitrogen-vacancy (NV) centers in diamond samples [10][11][12], or nuclear and electron spins realized as 31 P donors in 28 Si crystals [13] and Cr 3+ spins in Al 2 O 3 [14]. The coupling of qubit ensembles with a superconducting microwave resonators results in the formation of sub-wavelength quantum metamaterials [15][16][17][18][19]. The long-range interaction through a photon mode results in the formation of collective qubit states in such metamaterials [20,21], as Dicke model describes.…”

Section: Introductionmentioning

confidence: 99%

Synchronization of qubit ensembles under optimizedπ-pulse driving

2015

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We propose technique of simultaneous excitation of disordered qubits providing an effective suppression of inhomogeneous broadening in their spectral density. The technique is based on applying of optimally chosen π-pulse with non-rectangular smooth shape. We study excitation dynamics of an off-resonant qubit subjected to strong classical electromagnetic driving field with the fast reference frequency and slow envelope. Within this solution we optimize the envelope to achieve a preassigned accuracy in qubit synchronization.

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Dispersive Response of a Disordered Superconducting Quantum Metamaterial

Cited by 28 publications

References 20 publications

Dynamical Lamb effect in a tunable superconducting qubit-cavity system

Dynamical Lamb effect in a tunable superconducting qubit-cavity system

Spectrum of the Dicke model in a superconducting qubit-oscillator system

Synchronization of qubit ensembles under optimizedπ-pulse driving

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