Multiphoton Resonance Band and Bloch-Siegert Shift in a Bichromatically Driven Qubit

卷:6

Article

关键词: 2-LEVEL SYSTEM;    BEHAVIOR;    FIELD;    ATOM;   

DOI  :  10.1002/qute.202200191

来源: SCIE

【 摘 要 】

The resonance and dynamics of a qubit exposed to a strong aperiodic bichromatic field are studied by using a periodic counter-rotating hybridized rotating wave (CHRW) Hamiltonian, which is derived from the original Hamiltonian with the unitary transformations under a reasonable approximation and enables the application of the Floquet theory. It is found that the consistency between the CHRW results and numerically exact generalized-Floquet-theory (GFT) results in the valid regime of the former while the widely used rotating-wave approximation breaks down. It is illustrated that the resonance exhibits band structure and the Bloch-Siegert shifts induced by the counter-rotating couplings of the bichromatic field become notable at the multiphoton resonance band. In addition, the CHRW method is found to have a great advantage of efficiency over the GFT approach particularly in the low beat-frequency case where the latter converges very slowly. The present CHRW method provides a highly efficient way to calculate the resonance frequency incorporating the Bloch-Siegert shift and provides insights into the effects of the counter-rotating couplings of the bichromatic field in the strong-driving regimes.

【 授权许可】

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