Phase control of maximal atomic coherence

程广玲, 王一平, 陈爱喜

We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a single ?-type three-level fluxonium qubit, the coherent population trapping could be obtainable and it is very sensitive to the relative phase and amplitudes of the applied fields. When the relative phase is tuned to 0 or π, the maximal atomic coherence is present and coherent population trapping occurs. While for the choice of π /2, the atomic coherence becomes weak. Meanwhile, for the fixed relative phase π /2, the value of coherence would decrease with the increase of Rabi frequency of the external field coupled with two lower levels. The responsible physical mechanism is quantum interference induced by the control fields,which is indicated in the dressed-state representation. The microwave coherent phenomenon is present in our scheme,which will have potential applications in optical communication and nonlinear optics in solid-state devices.

Yu. P. Malakyan, Dmitry Budker, Valeriy V. Yashchuk +3 more

Yu. P. Malakyan, Dmitry Budker, Simon Rochester +3 more

Yueping Niu, Shangqing Gong, Ruxin Li +1 more

We propose a scheme for creating atomic coherent superpositions via stimulated Raman adiabatic passage in a Lambda-type system where the final state has twofold levels. In the employ of a control field, the presence of double dark states leads to two arbitrary coherent superposition states with equal amplitude but inverse relative phase without the condition of multi-photon resonance. In particular, two orthogonal maximal coherent superposition states are created when the control field is resonant with the transition of the twofold levels. This scheme can also be extended to manifold Lambda-type systems.

Guangling Cheng, Yi‐Ping Wang, Ai-Xi Chen

We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a single Δ-type three-level fluxonium qubit, the coherent population trapping could be obtainable and it is very sensitive to the relative phase and amplitudes of the applied fields. When the relative phase is tuned to 0 or π , the maximal atomic coherence is present and coherent population trapping occurs. While for the choice of π /2, the atomic coherence becomes weak. Meanwhile, for the fixed relative phase π /2, the value of coherence would decrease with the increase of Rabi frequency of the external field coupled with two lower levels. The responsible physical mechanism is quantum interference induced by the control fields, which is indicated in the dressed-state representation. The microwave coherent phenomenon is present in our scheme, which will have potential applications in optical communication and nonlinear optics in solid-state devices.

Takashi Nakajima, P. Lambropoulos