Injection locking replicates the frequency and phase of a driven oscillator in a target oscillator, with applications in electronic, mechanical, and optical systems, and lately in mesoscopic circuits. The technique requires the driven oscillator to be almost resonant with the target oscillator. This study uses a superconducting circuit to demonstrate injection locking in a well-controlled parametric microwave oscillator. The authors furthermore present another technique, $p\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c$ $l\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}k\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g$, that removes the constraint on detuning between the oscillators. This should impact any device that should not or cannot be close to resonant driving, as in quantum information processing.Injection locking replicates the frequency and phase of a driven oscillator in a target oscillator, with applications in electronic, mechanical, and optical systems, and lately in mesoscopic circuits. The technique requires the driven oscillator to be almost resonant with the target oscillator. This study uses a superconducting circuit to demonstrate injection locking in a well-controlled parametric microwave oscillator. The authors furthermore present another technique, $p\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c$ $l\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}k\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g$, that removes the constraint on detuning between the oscillators. This should impact any device that should not or cannot be close to resonant driving, as in quantum information processing.

arXiv:1904.01380Physical Review AppliedAug 16, 201917 citations

Quantum optics in superconducting circuits

Barry C. Sanders, Dmitry N. Chigrin

AIP conference proceedingsJan 1, 20112 citations

Quantum Optics with Superconducting Circuits and Hybrid Systems

Andreas J. Wallraff

Bulletin of the American Physical SocietyJun 2, 20140 citations

Realization of Superadiabatic Two-Qubit Gates Using Parametric Modulation in Superconducting Circuits

Ji Chu, Danyu Li, Xiaopei Yang +10 more

Fast, robust two-qubit gate operation with low susceptibility to crosstalk are the key to scalable quantum-information processing. A parametrically driven gate is inherently insensitive to crosstalk, while superadiabatic control can speed up the gate without losing accuracy. We propose and experimentally implement superadiabatic two-qubit gates using parametric modulation on superconducting quantum circuits. Our results demonstrate the preservation of adiabaticity at a gate speed close to the quantum limit, in addition to robustness against control instability. We demonstrate a controlled- $Z$ gate with an error rate of $5.8\mathrm{%}$, mainly limited by qubit decoherence, promising future improvement and scalable implementation.Fast, robust two-qubit gate operation with low susceptibility to crosstalk are the key to scalable quantum-information processing. A parametrically driven gate is inherently insensitive to crosstalk, while superadiabatic control can speed up the gate without losing accuracy. We propose and experimentally implement superadiabatic two-qubit gates using parametric modulation on superconducting quantum circuits. Our results demonstrate the preservation of adiabaticity at a gate speed close to the quantum limit, in addition to robustness against control instability. We demonstrate a controlled-$Z$ gate with an error rate of $5.8\mathrm{%}$, mainly limited by qubit decoherence, promising future improvement and scalable implementation.

arXiv:1906.02992Physical Review AppliedJun 4, 202051 citations

Superconducting Quantum Optics

ScienceFeb 11, 20100 citations

Parametric phase modulation in superconducting circuits

Zhuang Ma, X. F. Li, Hongyi Shi +4 more

Parametric modulation, valued for its versatility, is widely employed in superconducting circuits for quantum simulations and high-fidelity two-qubit gates. Conventionally, the qubit coupling strength is determined by the amplitude of the parametric flux pulse, which affects the qubit parameters dramatically. In this paper, we propose and implement a phase-modulation scheme to tune the interaction strength via adjustment of the relative phase between the parametric flux pulses applied to two coupled qubits. We characterize this modulation for sideband couplings, at both sweet and off-sweet spots, achieving a broad range of coupling strengths, as confirmed by both population dynamics and spectroscopy methods. This approach enables phase-controlled modulation of coupling strength, providing a promising candidate for parametrically driven quantum simulations and gate operations.Parametric modulation, valued for its versatility, is widely employed in superconducting circuits for quantum simulations and high-fidelity two-qubit gates. Conventionally, the qubit coupling strength is determined by the amplitude of the parametric flux pulse, which affects the qubit parameters dramatically. In this paper, we propose and implement a phase-modulation scheme to tune the interaction strength via adjustment of the relative phase between the parametric flux pulses applied to two coupled qubits. We characterize this modulation for sideband couplings, at both sweet and off-sweet spots, achieving a broad range of coupling strengths, as confirmed by both population dynamics and spectroscopy methods. This approach enables phase-controlled modulation of coupling strength, providing a promising candidate for parametrically driven quantum simulations and gate operations.

arXiv:2510.20192Physical Review AppliedNov 21, 20252 citations

Z

gate with an error rate of $5.8\mathrm{%}$, mainly limited by qubit decoherence, promising future improvement and scalable implementation.