Cavity squeezing by a quantum conductor

Mendes, Udenys Cabral; Mora, Christophe

doi:10.1088/1367-2630/17/11/113014

Cited by 28 publications

(44 citation statements)

References 65 publications

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“…In comparison to other recent works, we find that the resonator mode at frequency ω r plays the same role as virtual population of quasiparticle states in analogous normal-state systems [11,36,38,42]. Also in our system, squeezing does not emerge when V = 0.…”

Section: Comparison To Previous Worksupporting

confidence: 53%

Inelastic scattering of microwave radiation in the dynamical Coulomb blockade

Leppäkangas

Marthaler

2018

Phys. Rev. B

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We study scattering of propagating microwave fields by a DC-voltage biased Josephson junction. At sub-gap voltages, a small Josephson junction works merely as a non-linear boundary that can absorb, amplify, and diversely convert propagating microwaves. In the leading-order perturbation theory of the Josephson coupling energy, the spectral density and quadrature fluctuations of scattered thermal and coherent radiation can be described in terms of the well-known P (E) function. Applying this, we study how thermal and coherent radiation is absorbed and amplified in an Ohmic transmission line and in a circuit with a resonance frequency. We show when a coherent input can create a two-mode squeezed output. In addition, we evaluate scattering amplitudes between arbitrary photon-number (Fock) states, characterizing individual photon multiplication and absorption processes occuring at the junction. arXiv:1803.06654v3 [cond-mat.supr-con]

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Section: Comparison To Previous Worksupporting

confidence: 53%

Inelastic scattering of microwave radiation in the dynamical Coulomb blockade

Leppäkangas

Marthaler

2018

Phys. Rev. B

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“…The last term characterizes the radiation emitted by the junction and it gives rise to both current fluctuations and a deterministic response to the applied voltages [43,44]. , we take advantage of the weak TL-junction coupling πZ 0 /R K 1 (for a typical Z 0 = 50 Ω TL impedance [9,10], with R K 25.8 kΩ the quantum of resistance) and computeÎ J [ω] to second-order in the TL-junction coupling [32,43]. In the time domain and for weak coupling to the environment, the current operator, in the Heisenberg picture, takes the form…”

Section: Modelmentioning

confidence: 99%

Parametric amplification and squeezing with an ac- and dc-voltage biased superconducting junction

et al. 2019

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We theoretically investigate a near-quantum-limited parametric amplifier based on the nonlinear dynamics of quasiparticles flowing through a superconducting-insulator-superconducting junction. Photon-assisted tunneling, resulting from the combination of dc-and ac-voltage bias, gives rise to a strong parametric interaction for the electromagnetic modes reflected by the junction coupled to a transmission line. We show phase-sensitive and phase-preserving amplification, together with single-and two-mode squeezing. For an aluminum junction pumped at twice the center frequency, ω0/2π = 6 GHz, we predict narrow-band phase-sensitive amplification of microwaves signals to more than 20 dB, and broadband phase-preserving amplification of 20 dB over a 1.2 GHz 3-dB bandwidth. We also predict single-and two-mode squeezing reaching more than -12 dB over 5.3 GHz 3-dB bandwidth. Moreover, with a simple impedance matching circuit, we demonstrate 3 dB bandwidth reaching 4.3 GHz for 20 dB of gain. A key feature of the device is that its performance can be controlled in-situ with the applied dc-and ac-voltage biases.arXiv:1802.07323v2 [cond-mat.mes-hall]

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“…A Josephson-photonics setup, as pioneered by the experimental groups at Saclay/Grenoble [21,25,26] and Dartmouth [22][23][24] and subsequently extensively investigated theoretically [23,[28][29][30][31][32][33][34][35][36][37][38][39][40][41], uses a Josephson junction biased by an external dc voltage V to create microwave excitations in two or more series-connected LC oscillators with frequencies w = L C 1 q q q , see figure 1(a). These oscillators parallel the microwave stripline cavities coupled to qubits in standard circuit-QED setups, where, however, there is no dc-current path through the system.…”

Section: Josephson-photonics Device As Entanglement Sourcementioning

confidence: 99%

Generating entangled quantum microwaves in a Josephson-photonics device

2017

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When connecting a voltage-biased Josephson junction in series to several microwave cavities, a Cooper-pair current across the junction gives rise to a continuous emission of strongly correlated photons into the cavity modes. Tuning the bias voltage to the resonance where a single Cooper pair provides the energy to create an additional photon in each of the cavities, we demonstrate the entangling nature of these creation processes by simple witnesses in terms of experimentally accessible observables. To characterize the entanglement properties of the such created quantum states of light to the fullest possible extent, we then proceed to more elaborate entanglement criteria based on the knowledge of the full density matrix and provide a detailed study of bi-and multipartite entanglement. In particular, we illustrate how due to the relatively simple design of these circuits changes of experimental parameters allow one to access a wide variety of entangled states differing, e.g., in the number of entangled parties or the dimension of state space. Such devices, besides their promising potential to act as a highly versatile source of entangled quantum microwaves, may thus represent an excellent natural testbed for classification and quantification schemes developed in quantum information theory.properly choosing an elaborate pulse scheme, in principle, any entangled state could be created, it is typically a maximally entangled or another simple pure entangled state which such experiments aim for.The creation of multipartite or other more complex entangled states requires increasingly complex pulse schemes. These are reachable in such systems since one can build on the immense research effort (and the resulting amazing progress in performance and control) which has been spent on these standard circuitquantum-electrodynamics (QED) setups as part of the larger quest for universal quantum computing. Here we argue, however, that combining two key elements of circuit-QED setups, namely, Josephson junctions and microwave cavities, in a much simpler, less demanding device can offer an alternative, fully tunable and versatile entanglement-generating source.Recently developed Josephson-photonics devices [21][22][23][24], which already demonstrated their potential as a source of nonclassical microwave light [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], seem to be logical candidates for this task. In fact, the next generation of setups currently being under fabrication is designed to explore bipartite photon creation processes. The goals of the present work are thus twofold: to make detailed and quantitative predictions about entanglement properties of this new class of superconducting devices and to give instructions how to vary and design experimental parameters accordingly. In this respect, the simple bipartite case is only the first step. As we will show, Josephson-photonics architectures allow one by comparatively simple changes of experimental parameters to also access multipartite situations, the characteriz...

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Cavity squeezing by a quantum conductor

Cited by 28 publications

References 65 publications

Inelastic scattering of microwave radiation in the dynamical Coulomb blockade

Inelastic scattering of microwave radiation in the dynamical Coulomb blockade

Parametric amplification and squeezing with an ac- and dc-voltage biased superconducting junction

Generating entangled quantum microwaves in a Josephson-photonics device

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