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Optical selection rules and phase-dependent adiabatic state control in a superconducting quantum circuit

Yu-xi Liu·J. Q. You·L. F. Wei·C. P. Sun·Franco Nori
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Abstract

We analyze the optical selection rules of the microwave-assisted transitions in a flux qubit superconducting quantum circuit (SQC). We show that the parities of the states relevant to the superconducting phase in the SQC are well-defined when the external magnetic flux $Φ_{e}=Φ_{0}/2$, then the selection rules are same as the ones for the electric-dipole transitions in usual atoms. When $Φ_{e}\neq Φ_{0}/2$, the symmetry of the potential of the artificial "atom'' is broken, a so-called $Δ$-type "cyclic" three-level atom is formed, where one- and two-photon processes can coexist. We study how the population of these three states can be selectively transferred by adiabatically controlling the electromagnetic field pulses. Different from $Λ$-type atoms, the adiabatic population transfer in our three-level $Δ$-atom can be controlled not only by the amplitudes but also by the phases of the pulses.

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Yu-xi Liu, J. Q. You, L. F. Wei, C. P. Sun, Franco Nori. 2005-08-27. Optical selection rules and phase-dependent adiabatic state control in a superconducting quantum circuit. https://doi.org/10.1103/physrevlett.95.087001

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