Landau-Zener tunnelling in dissipative circuit QED

Dynamics of dissipative Landau-Zener transitions

A non-perturbative treatment, the Dirac-Frenkel time-dependent variation is employed to examine dynamics of the Landau-Zener model with both diagonal and off-diagonal qubit-bath coupling using the multiple Davydov trial states. It is shown that steady-state transition probabilities agree with analytical predictions at long times. Landau-Zener dynamics at intermediate times is little affected by diagonal coupling, and is found to be determined by off-diagonal coupling and tunneling strength between two diabatic states. We investigate effects of bath spectral densities, coupling strengths and in…

Effective Landau-Zener transitions in circuit dynamical Casimir effect with time-varying modulation frequency

We consider the dissipative single-qubit circuit QED architecture in which the atomic transition frequency undergoes a weak external time-modulation. For sinusoidal modulation with linearly varying frequency we derive effective Hamiltonians that resemble the Landau-Zener problem of finite duration associated to a two- or multi-level systems. The corresponding off-diagonal coupling coefficients originate either from the rotating or the counter-rotating terms in the Rabi Hamiltonian, depending on the values of the modulation frequency. It is demonstrated that in the dissipation less case one can…

光放大朗道-齐纳电导在带隙石墨烯单层中的研究：光催化真空不稳定性的一种模拟

Light-amplified Landau-Zener conductivity in gapped graphene monolayers: a simulacrum of photo-catalyzed vacuum instability

该研究探讨带隙石墨烯中光辅助隧穿电流，发现光催化电流远超纯强场电流，为QED施温格机制提供模拟。

Accelerating adiabatic protocols for entangling two qubits in circuit QED

We introduce a method to speed up adiabatic protocols for creating entanglement between two qubits dispersively coupled to a transmission line, while keeping fidelities high and maintaining robustness to control errors. The method takes genuinely adiabatic sweeps, ranging from a simple Landau-Zener drive to boundary cancellation methods and local adiabatic drivings, and adds fast oscillations to speed up the protocol while canceling unwanted transitions. We compare our protocol with existing adiabatic methods in a state-of-the-art parameter range and show substantial gains. Numerical simulatio…