Geometric phases in qubit-oscillator system beyond conventional rotating-wave approximation

杨青, 杨名, 曹卓良

Vittorio Peano, Michael Marthaler, M. I. Dykman

S. Abdel‐Khalek, Y. S. El-Saman, Idir Mechai +1 more

Yue-Ming Wang, Guan Du, Liang Jiu-Qing

In this work we investigated the geometric phases of a qubit-oscillator system beyond the conventional rotating-wave approximation. We find that in the limiting of weak coupling the results coincide with that obtained under rotating-wave approximation while there exists an increasing difference with the increase of coupling constant. It was shown that the geometric phase is symmetric with respect to the sign of the detuning of the quantized field from the one-photon resonance under the conventional rotating-wave approximation while a red-blue detuning asymmetry occurs beyond the conventional rotating-wave approximation.

Anonymous, Zhihui Wang, Tanay Roy +2 more

David Zueco, Georg M. Reuther, Sigmund Kohler +1 more

We generalize the dispersive theory of the Jaynes-Cummings model beyond the frequently employed rotating-wave approximation (RWA) in the coupling between the two-level system and the resonator. For a detuning sufficiently larger than the qubit-oscillator coupling, we diagonalize the non-RWA Hamiltonian and discuss the differences to the known RWA results. Our results extend the regime in which dispersive qubit readout is possible. If several qubits are coupled to one resonator, an effective qubit-qubit interaction of Ising type emerges, whereas RWA leads to isotropic $XY$ interaction. This impacts on the entanglement characteristics of the qubits.