Magnus expansion for a chirped quantum two-level system
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Date
2018-06-07
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American Physical Society
Abstract
We derive a Magnus expansion for a frequency chirped quantum two-level system. We obtain a time-independent effective Hamiltonian which generates a stroboscopic time evolution. At lowest order the according dynamics is identical to results from using a rotating wave approximation. We determine, furthermore, also the next higher-order corrections within our expansion scheme in correspondence to the Bloch-Siegert shifts for harmonically driven systems. Importantly, our scheme can be extended to more complicated systems, i.e., even many-body systems.
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Keywords
Quantum optics, Bloch-Siegert shift, Complicated systems, Magnus expansion