Effective Hamiltonian of the Jaynes–Cummings model beyond rotating-wave approximation |
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作者单位: | Department of Physics, Capital Normal University, Beijing 100048, China |
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基金项目: | Project supported by the National Natural Science Foundation of China (Grant No. 11875195) and the Foundation of Beijing Education Committees, China (Grant Nos. CIT&TCD201804074 and KZ201810028043). |
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摘 要: | The Jaynes–Cummings model with or without rotating-wave approximation plays a major role to study the interaction between atom and light. We investigate the Jaynes–Cummings model beyond the rotating-wave approximation. Treating the counter-rotating terms as periodic drivings, we solve the model in the extended Floquet space. It is found that the full energy spectrum folded in the quasi-energy bands can be described by an effective Hamiltonian derived in the highfrequency regime. In contrast to the Z_2 symmetry of the original model, the effective Hamiltonian bears an enlarged U(1)symmetry with a unique photon-dependent atom-light detuning and coupling strength. We further analyze the energy spectrum, eigenstate fidelity and mean photon number of the resultant polaritons, which are shown to be in accordance with the numerical simulations in the extended Floquet space up to an ultra-strong coupling regime and are not altered significantly for a finite atom-light detuning. Our results suggest that the effective model provides a good starting point to investigate the rich physics brought by counter-rotating terms in the frame of Floquet theory.
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收稿时间: | 2020-11-17 |
Effective Hamiltonian of the Jaynes-Cummings model beyond rotating-wave approximation |
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Affiliation: | Department of Physics, Capital Normal University, Beijing 100048, China |
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Abstract: | The Jaynes-Cummings model with or without rotating-wave approximation plays a major role to study the interaction between atom and light. We investigate the Jaynes-Cummings model beyond the rotating-wave approximation. Treating the counter-rotating terms as periodic drivings, we solve the model in the extended Floquet space. It is found that the full energy spectrum folded in the quasi-energy bands can be described by an effective Hamiltonian derived in the high-frequency regime. In contrast to the Z2 symmetry of the original model, the effective Hamiltonian bears an enlarged U(1) symmetry with a unique photon-dependent atom-light detuning and coupling strength. We further analyze the energy spectrum, eigenstate fidelity and mean photon number of the resultant polaritons, which are shown to be in accordance with the numerical simulations in the extended Floquet space up to an ultra-strong coupling regime and are not altered significantly for a finite atom-light detuning. Our results suggest that the effective model provides a good starting point to investigate the rich physics brought by counter-rotating terms in the frame of Floquet theory. |
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Keywords: | Jaynes-Cummings model Floquet theory high-frequency approximation |
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