| 1. |
- Krantz, Philip, 1984, et al.
(författare)
-
Investigation of nonlinear effects in Josephson parametric oscillators used in circuit quantum electrodynamics
- 2013
-
Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 15, s. (article nr) 105002-
-
Tidskriftsartikel (refereegranskat)abstract
- We experimentally study the behavior of a parametrically pumped nonlinear oscillator, which is based on a superconducting quarter wavelength resonator, and is terminated by a flux-tunable superconducting quantum interference device. We extract parameters for two devices. In particular, we study the effect of the nonlinearities in the system and compare to theory. The Duffing nonlinearity is determined from the probe-power dependent frequency shift of the oscillator, and the nonlinearity related to the parametric flux pumping, is determined from the pump amplitude for the onset of parametric oscillations. Both nonlinearities depend on the parameters of the device and can be tuned in situ by the applied dc flux. We also suggest how to cancel the effect of by adding a small dc flux and a pump tone at twice the pump frequency.
|
|
| 2. |
- Shumeiko, Vitaly, 1946, et al.
(författare)
-
Parametric Effects in Circuit Quantum Electrodynamics (Review Article)
- 2019
-
Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 45:08, s. 995-1017
-
Forskningsöversikt (refereegranskat)abstract
- We review recent advances in the research on quantum parametric phenomena in superconducting circuits with Josephson junctions. We discuss physical processes in parametrically driven tunable cavity and outline theoretical foundations for their description. Amplification and frequency conversion are discussed in detail for degenerate and non-degenerate parametric resonance, including quantum noise squeezing and photon entanglement. Experimental advances in this area played decisive role in successful development of quantum limited parametric amplifiers for superconducting quantum information technology. We also discuss nonlinear down-conversion processes and experiments on self-sustained parametric and subharmonic oscillations.
|
|
| 3. |
- Simoen, Michael Roger Andre, 1986, et al.
(författare)
-
Characterization of a multimode coplanar waveguide parametric amplifier
- 2015
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 118:15, s. 154501-
-
Tidskriftsartikel (refereegranskat)abstract
- We characterize a Josephson parametric amplifier based on a flux-tunable quarter-wavelength resonator. The fundamental resonance frequency is ∼1 GHz, but we use higher modes of the resonator for our measurements. An on-chip tuning line allows for magnetic flux pumping of the amplifier. We investigate and compare degenerate parametric amplification, involving a single mode, and nondegenerate parametric amplification, using a pair of modes. We show that we reach quantum-limited noise performance in both cases.
|
|
| 4. |
- Svensson, Ida-Maria, 1988, et al.
(författare)
-
Microwave photon generation in a doubly tunable superconducting resonator
- 2018
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 969:1
-
Konferensbidrag (refereegranskat)abstract
- We have created a doubly tunable resonator, with the intention to simulate relativistic motion of the resonator boundaries in real space. Our device is a superconducting coplanar-waveguide microwave resonator, with fundamental resonant frequency ω 1 / (2 π ) ~ 5 GHz. Both of its ends are terminated to ground via dc-SQUIDs, which serve as magnetic-flux-controlled inductances. Applying a flux to either SQUID allows the tuning of ω 1 / (2 π ) by approximately 700 MHz. Using two separate on-chip magnetic-flux lines, we modulate the SQUIDs with two tones of equal frequency, close to 2 ω 1 . We observe photon generation, at ω 1 , above a certain pump amplitude threshold. By varying the relative phase of the two pumps we are able to control this threshold, in good agreement with a theoretical model. At the same time, some of our observations deviate from the theoretical predictions, which we attribute to parasitic couplings resulting in current driving of the SQUIDs
|
|
| 5. |
- Wustmann, Waltraut, 1982, et al.
(författare)
-
Nondegenerate Parametric Resonance in a Tunable Superconducting Cavity
- 2017
-
Ingår i: Physical Review Applied. - 2331-7019. ; 8:2
-
Tidskriftsartikel (refereegranskat)abstract
- We develop a theory for nondegenerate parametric resonance in a tunable superconducting cavity. We focus on nonlinear effects that are caused by nonlinear Josephson elements connected to the cavity. We analyze parametric amplification in a strong nonlinear regime at the parametric-instability threshold, and we calculate maximum gain values. Above the threshold, in the parametric-oscillator regime, the cavity linear response diverges at the oscillator frequency at all pump strengths. We show that this divergence is related to the continuous degeneracy of the free oscillator state with respect to the phase. Applying on-resonance input lifts the degeneracy and removes the divergence. We also investigate quantum noise squeezing. It is shown that in the strong amplification regime, the noise undergoes four-mode squeezing, and that, in this regime, the output signal-to-noise ratio can significantly exceed the input value. We also analyze the intermode frequency conversion and identify the parameters at which full conversion is achieved.
|
|
| 6. |
- Wustmann, Waltraut, 1982, et al.
(författare)
-
Parametric resonance in tunable superconducting cavities
- 2013
-
Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 87:18
-
Tidskriftsartikel (refereegranskat)abstract
- We develop a theory of parametric resonance in tunable superconducting cavities. The nonlinearity introduced by the superconducting quantum interference device (SQUID) attached to the cavity and damping due to connection of the cavity to a transmission line are taken into consideration. We study in detail the nonlinear classical dynamics of the cavity field below and above the parametric threshold for the degenerate parametric resonance, featuring regimes of multistability and parametric radiation. We investigate the phase-sensitive amplification of external signals on resonance, as well as amplification of detuned signals, and relate the amplifier performance to that of linear parametric amplifiers. We also discuss applications of the device for dispersive qubit readout. Beyond the classical response of the cavity, we investigate small quantum fluctuations around the amplified classical signals. We evaluate the noise power spectrum both for the internal field in the cavity and the output field. Other quantum-statistical properties of the noise are addressed such as squeezing spectra, second-order coherence, and two-mode entanglement.
|
|
| 7. |
- Wustmann, Waltraut, 1982, et al.
(författare)
-
Theory of parametric resonance in tunable superconducting microwave cavities
- 2014
-
Ingår i: Optics InfoBase Conference Papers. - Washington, D.C. : OSA. - 2162-2701. - 9781557529954
-
Konferensbidrag (refereegranskat)abstract
- We present detailed theory of parametric resonance in high quality tunable superconducting cavity. Nonlinear amplification of classical signals and quantum noise characteristics are calculated for broad range of device parameters below and above parametric threshold. © OSA 2014.
|
|
| 8. |
- Wustmann, Waltraut, 1982, et al.
(författare)
-
Theory of two-mode parametric resonance in superconducting cavity
- 2017
-
Ingår i: Optics InfoBase Conference Papers. - 2162-2701. - 9781557528209 ; Part F73-QIM 2017
-
Konferensbidrag (refereegranskat)abstract
- Nonlinear amplification, and nonlinear frequency conversion between cavity eigen modes is theoretically investigated. Parametric oscillation, and gains below and above instability threshold are analyzed. Vacuum noise squeezing is evaluated and output noise-tosignal ratio is calculated.
|
|
| 9. |
- Zhou, X., et al.
(författare)
-
High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID array
- 2014
-
Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 89:21, s. Article No. 214517-
-
Tidskriftsartikel (refereegranskat)abstract
- We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of eight superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude gain x bandwidth above 60 MHz, and a 1 dB compression point of -123 dBm at 20 dB gain are obtained in the nondegenerate mode of operation. Phase-sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array.
|
|
