A wideband, low-noise superconducting amplifier with high dynamic range

Eom, Byeong Ho; Day, Peter; Leduc, H. G.; Žmuidzinas, J.

doi:10.1038/nphys2356

Cited by 328 publications

(282 citation statements)

References 34 publications

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“…Indeed recent works 30 discuss mode engineering of the resonant modes of a chain by varying the junction parameters. This approach might be extended to also engineer the non-linear interaction between the modes and thus tailor an active medium for the use in travelling wave parametric amplifiers 31,32 .…”

Section: Discussionmentioning

confidence: 99%

Kerr coefficients of plasma resonances in Josephson junction chains

et al. 2015

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We present an experimental and theoretical analysis of the self-and cross-Kerr effect of extended plasma resonances in Josephson junction chains. We calculate the Kerr coefficients by deriving and diagonalizing the Hamiltonian of a linear circuit model for the chain and then adding the Josephson non-linearity as a perturbation. The calculated Kerr-coefficients are compared with the measurement data of a chain of 200 junctions. The Kerr effect manifests itself as a frequency shift that depends linearly on the number of photons in a resonant mode. By changing the input power on a low signal level, we are able to measure this shift. The photon number is calibrated using the self-Kerr shift calculated from the sample parameters. We then compare the measured cross-Kerr shift with the theoretical prediction, using the calibrated photon number.

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Section: Discussionmentioning

confidence: 99%

Kerr coefficients of plasma resonances in Josephson junction chains

et al. 2015

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“…Our amplifier achieves a maximal gain of 20 dB, which is comparable to the gain of similar superconducting parametric amplifiers. 14,16,17 However, the experiments reveal two unknown features, namely two branches of high amplification of the idler signal and in the case of a bias flux of Φ = Φ 0 /2 a periodical pattern of the gain dependent on the flux itself.…”

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confidence: 99%

“…11 These successful experiments have motivated the development of new parametric amplifiers based on Josephson junctions, 12,13 DC squids, [13][14][15] high kinetic inductance of weak links, 16 or disordered superconductors. 17 Superconducting qubits also exhibit a strong nonlinearity 18 and therefore are good candidates for parameteric amplification. 19 In this paper, we demonstrate parametric amplification exploiting the nonlinearity of a pair of superconducting flux qubits coupled to a coplanar waveguide resonator.…”

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Parametric amplification by coupled flux qubits

et al. 2014

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We report the parametric amplification of a microwave signal in a Kerr medium formed from superconducting qubits. Two mutually coupled flux qubits, embedded in the current antinode of a superconducting coplanar waveguide resonator, are used as a nonlinear element. Shared Josephson junctions provide the qubit-resonator coupling, resulting in a device with a measured gain of about 20 dB. We argue, that this arrangement represents a unit cell which can be straightforwardly extended to a quasi one-dimensional quantum metamaterial with a large tunable Kerr nonlinearity.New developments in circuit quantum electrodynamics has resulted in the possibility of signal detection close to and even below the standard quantum limit. This work was motivated by microwave quantum engineering, 1-3 including quantum information processing devices. 4,5 The sensitivity of cryogenic semiconductor amplifiers with reasonable power consumption in both the MHz 6 and GHz (commercially available) range are all currently above the quantum limit. At very low temperatures it is quite natural to use the parametric effect for amplification which adds no additional noise to the signal. In practice, a nonlinear superconducting oscillator can be used for this purpose. 7,8 In this case, usually a nonlinearity of superconducting weak links 9,10 is exploited. Very recently the squeezing of quantum noise and its measurement below the standard quantum limit was demonstrated. 11 These successful experiments have motivated the development of new parametric amplifiers based on Josephson junctions, 12,13 DC squids, 13-15 high kinetic inductance of weak links, 16 or disordered superconductors. 17 Superconducting qubits also exhibit a strong nonlinearity 18 and therefore are good candidates for parameteric amplification. 19 In this paper, we demonstrate parametric amplification exploiting the nonlinearity of a pair of superconducting flux qubits coupled to a coplanar waveguide resonator. These qubits represent a unit cell which can be easily extended to a one-dimensional array. Such an array can be considered as a medium with large Kerr nonlinearity. Neglecting the interactions between the modes, a nonlinear oscillator can be described by the Hamiltonian 20where is the reduced Planck constant, a and a † are the creation and the annihilation operators, ω n is the angular frequency of the n-th mode of the oscillator, and K n is the Kerr constant, which is a measure of the nonlinearity in the system. The qubits contribute to the nonlinear inductance of the resonator per unit length according tõ Then, the Kerr constant can be calculated by 20where u n (x) = 2 Lrl sin( nπx l ), l is the length of the resonator,L r the linear inductance of the resonator per unit length, I r the current flowing in the resonator, I cqr the critical current of the Josephson junction shared by the resonator and qubit, andL i are the Taylor coefficients characterizing the nonlinearity of the inductance. The Kerr constant can be determined for every nonlinear medium. In optics, the Kerr c...

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“…In practice however, good device performance and bandwidth of TWPAs is limited by the requirement of phase-matching (though see Ref. 26 for recent progress in the microwave domain).…”

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confidence: 99%

Quantum-Limited Amplification via Reservoir Engineering

2014

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We describe a new kind of phase-preserving quantum amplifier which utilizes dissipative interactions in a parametrically-coupled three-mode bosonic system. The use of dissipative interactions provides a fundamental advantage over standard cavity-based parametric amplifiers: large photon number gains are possible with quantum-limited added noise, with no limitation on the gain-bandwidth product. We show that the scheme is simple enough to be implemented both in optomechanical systems and in superconducting microwave circuits.PACS numbers: 42.65. Yj, 03.65.Ta, 42.50.Wk, 07.10.Cm Introduction-The past few years have seen a resurgence of interest in amplifiers working near the fundamental limits set by quantum mechanics [1], in contexts varying from quantum information processing in circuits [2][3][4], to radio astronomy [5], to ultra-sensitive force detection (e.g., for gravity wave detection [6]). The standard paradigm for a quantum-limited, phasepreserving amplifier is the non-degenerate parametric amplifier (NDPA) [7][8][9][10], which is based on a coherent interaction involving three bosonic modes (pump, signal and idler). This interaction simply converts a pump mode photon into two photons, one in the signal mode, the other in the idler mode. The result is that weak signals incident on the signal mode are amplified, with the minimum possible added noise. There has been remarkable progress in realizing such amplifiers using superconducting circuits [11][12][13][14][15][16][17][18]. This in turn has enabled a number of breakthroughs, from the measurement of mechanical motion near the quantum limit [19], to the measurement of quantum jumps of a superconducting qubit [20,21] and the implementation of quantum feedback schemes [22,23].Despite their many advantages, standard cavity-based parametric amplifiers suffer from the limitation of having a fixed gain-bandwidth product: as one increases the gain of the amplifier, one also reduces the range of signal frequencies over which there is amplification. This is a fundamental consequence of the amplification mechanism, which involves introducing effective negative damping to the signal mode. The consequent reduced damping rate determines the amplification, but also sets the amplification bandwidth (see, e.g., [3]). This tradeoff between gain and bandwidth can severely limit the utility of cavity-based parametric amplifiers in many applications. Traveling-wave parametric amplifiers (TWPAs) [24,25] do not use cavities and are in principle not limited in the same way. In practice however, good device performance and bandwidth of TWPAs is limited by the requirement of phase-matching (though see Ref. 26 for recent progress in the microwave domain).In this work, we introduce a new approach for quantum-limited amplification based now on three local-

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A wideband, low-noise superconducting amplifier with high dynamic range

Cited by 328 publications

References 34 publications

Kerr coefficients of plasma resonances in Josephson junction chains

Kerr coefficients of plasma resonances in Josephson junction chains

Parametric amplification by coupled flux qubits

Quantum-Limited Amplification via Reservoir Engineering

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