Microwave-induced amplitude- and phase-tunable qubit-resonator coupling in circuit quantum electrodynamics

Abstract

In the circuit quantum electrodynamics architecture, both the resonance frequency and the coupling of superconducting qubits to microwave field modes can be controlled via external electric and magnetic fields to explore qubit -photon dynamics in a wide parameter range. Here, we experimentally demonstrate and analyze a scheme for tuning the coupling between a transmon qubit and a microwave resonator using a single coherent drive tone. We treat the transmon as a three-level system with the qubit subspace defined by the ground and the second excited states. If the drive frequency matches the difference between the resonator and the qubit frequency, a Jaynes-Cummings type interaction is induced, which is tunable both in amplitude and phase. We show that coupling strengths of about 10 MHz can be achieved in our setup, limited only by the anharmonicity of the transmon qubit. This scheme has been successfully used to generate microwave photons with controlled temporal shape [Pechal et al., Phys. Rev. X 4, 041010 (2014)] and can be directly implemented with superconducting quantum devices featuring larger anharmonicity for higher coupling strengths.

Advances in quantum control of three‐level superconducting circuit architectures

“…This is a generalization of the switchable coupling scheme recently introduced in Ref. . In our case we must cancel the potentially dangerous dynamical Stark shift , which can be done by phase modulation of the control fields as explained in §, whereas S 0 is cancelled by proper static detunings.…”

Pulsed Reset Protocol for Fixed-Frequency Superconducting Qubits

“…This avoids introducing a second resonator used for reset and thus saves space on the chip. Similarly to [22], our reset protocol is based on an induced Rabi oscillation between the second-excited state of a superconducting transmontype qubit and a harmonic oscillator [23]. This technique has been employed to generate shaped microwave photons [24] to establish entanglement between remote qubits [25][26][27].…”

Antidynamical Casimir effect as a resource for work extraction

“…Ultimately, the photon creation relies on the presence of the counter-rotating terms (CRT) in the Rabi Hamiltonian (RH) [22], usually neglected under the rotating wave approximation (RWA) [23,24]. The time-dependent Rabi model can be implemented experimentally in the current circuit Quantum Electrodynamics (circuit QED) architecture [25][26][27][28][29][30][31][32][33][34] with artificial superconducting atoms coupled to microwave resonators, where DCE analogues were already observed both in a single-mirror and a cavity configurations [35,36]. However, the DCE is not the only relevant effect that arises * adodonov@fis.unb.br from the combination of the CRT and the temporal modulation of the system parameters.…”