Circuit QED: superconducting qubits coupled to microwave photons

2014 ◽  
pp. 113-256 ◽  
Author(s):  
S. M. Girvin
Keyword(s):  
Superconducting Qubits ◽  
Circuit Qed

scholarly journals Bogoliubov quasiparticles in superconducting qubits

2021 ◽  
Author(s):  
Leonid Glazman ◽  
Gianluigi Catelani
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Adverse Effects ◽  
Quantum Information Processing ◽  
Photon Emission ◽  
Three Dimensional ◽  
Degree Of Freedom ◽  
Superconducting Qubits ◽  
Relaxation Rates ◽  
Circuit Qed

Extending the qubit coherence times is a crucial task in building quantum information processing devices. In the three-dimensional cavity implementations of circuit QED, the coherence of superconducting qubits was improved dramatically due to cutting the losses associated with the photon emission. Next frontier in improving the coherence includes the mitigation of the adverse effects of superconducting quasiparticles. In these lectures, we review the basics of the quasiparticles dynamics, their interaction with the qubit degree of freedom, their contribution to the qubit relaxation rates, and approaches to control their effect.

Entanglement Dynamics of Strongly-AC-Driven Superconducting Qubits in Circuit QED

2011 ◽  
Vol 56 (2) ◽  
pp. 317-321 ◽  
Author(s):  
Zhen-Gang Shi ◽  
Xiong-Wen Chen ◽  
Wei Wen ◽  
Shao-Hua Xiang ◽  
Ke-Hui Song
Keyword(s):  
Superconducting Qubits ◽  
Entanglement Dynamics ◽  
Circuit Qed

scholarly journals Independent, extensible control of same-frequency superconducting qubits by selective broadcasting

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Serwan Asaad ◽  
Christian Dickel ◽  
Nathan K Langford ◽  
Stefano Poletto ◽  
Alessandro Bruno ◽  
...  
Keyword(s):  
Quantum Information ◽  
Control Strategy ◽  
Large Scale ◽  
Error Threshold ◽  
Superconducting Qubits ◽  
Circuit Qed ◽  
Single Qubit ◽  
Surface Code

Abstract A critical ingredient for realising large-scale quantum information processors will be the ability to make economical use of qubit control hardware. We demonstrate an extensible strategy for reusing control hardware on same-frequency transmon qubits in a circuit QED chip with surface-code-compatible connectivity. A vector switch matrix enables selective broadcasting of input pulses to multiple transmons with individual tailoring of pulse quadratures for each, as required to minimise the effects of leakage on weakly anharmonic qubits. Using randomised benchmarking, we compare multiple broadcasting strategies that each pass the surface-code error threshold for single-qubit gates. In particular, we introduce a selective broadcasting control strategy using five pulse primitives, which allows independent, simultaneous Clifford gates on arbitrary numbers of qubits.

STUDY ON QUANTUM CORRELATIONS FOR CIRCUIT QED STATES

2013 ◽  
Vol 27 (13) ◽  
pp. 1350056 ◽  
Author(s):  
Y. H. JI ◽  
Y. M. LIU
Keyword(s):  
Quantum Discord ◽  
Relative Phase ◽  
Photon Number ◽  
Quantum Correlations ◽  
Superconducting Qubits ◽  
Squeezed State ◽  
Cavity Field ◽  
Circuit Qed ◽  
Study Results ◽  
Average Photon Number

We investigate the dynamic evolution behaviors of entanglement and geometric quantum discord of coupled superconducting qubits in circuit QED system. We carefully analyze the effect of cavity field quantum state on the quantum entanglement and quantum correlations dynamic behaviors of coupling superconducting qubits. The results show that when the cavity field is in coherent state, with the average photon number increasing, the quantum discord death (including entanglement death) would become more difficult to appear, that is to say prolonging the survival time of quantum correlations will be a benefit for keeping the quantum correlations. When the cavity field is in squeezed state, the squeezed amplitude parameters are all too big or too small to keep the system quantum correlations. However, the further study results show that with the initial relative phase of coupling superconducting increasing, qubits can also keep the quantum correlations.

scholarly journals Development and characterization of a flux-pumped lumped element Josephson parametric amplifier

2019 ◽  
Vol 198 ◽  
pp. 00008
Author(s):  
Martina Esposito ◽  
Joseph Rahamim ◽  
Andrew Patterson ◽  
Matthias Mergenthaler ◽  
James Wills ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Quantum Noise ◽  
Parametric Amplifier ◽  
Superconducting Qubits ◽  
Single Shot ◽  
Circuit Qed ◽  
Figures Of Merit ◽  
Lumped Element ◽  
Lc Resonator

Josephson parametric amplification is a tool of paramount importance in circuit-QED especially for the quantum-noise-limited single-shot read-out of superconducting qubits. We developed a Josephson parametric amplifier (JPA) based on a lumped-element LC resonator, in which the inductance L is composed by a geometric inductance and an array of 4 superconducting quantum interference devices (SQUIDs). We characterized the main figures of merit of the device, obtaining a −3 dB bandwidth BW = 15 MHz for a gain G = 21 dB and a 1 dB compression point P1dB = −115 dBm. The obtained results are promising for the future use of such JPA as the first stage of amplification for single-shot readout of superconducting qubits.

Effects of Microwave Field on Supercurrents and Entanglement in Measurement of Qubit-State Readout

2013 ◽  
Vol 333-335 ◽  
pp. 72-76
Author(s):  
Ju Ju Hu ◽  
Xiang Dong Wan ◽  
Qiang Ke ◽  
Ying Hua Ji
Keyword(s):  
Quantum Entanglement ◽  
Quantum State ◽  
Microwave Field ◽  
Qubit State ◽  
Superconducting Qubits ◽  
Cavity Field ◽  
Circuit Qed ◽  
Dynamical Behaviors ◽  
Single Sideband

We carefully investigate the effect of cavity field quantum state on the quantum entanglement and supercurrent dynamical behaviors of coupling superconducting qubits in circuit QED system. The results show that not only the time-evolving dynamics of entanglement exhibit collapse and revival oscillation behaviors，but also that the single sideband envelope of current is almost similar with the time-evolving curve of entanglement.

Shortcut-based quantum gates on superconducting qubits in circuit QED

2021 ◽  
Author(s):  
Zheng-Yin Zhao ◽  
Run-Ying Yan ◽  
Zhi-Bo Feng
Keyword(s):  
Superconducting Qubits ◽  
Quantum Gates ◽  
Circuit Qed
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