Multifrequency resonance transitions between quasi-energy states

V. Yu. Finkel'Shteǐn

J.A. Hermann, S. Swain

Igor' M Bel'dyugin, A. A. Stepanov, Vladimir A. Shcheglov

A theory is developed of interference interaction of multifrequency counterpropagating laser waves in many-level resonant media. Closed equations are derived for a degenerate two-wave interaction of multifrequency radiation due to cascade transitions in many-level absorbing and amplifying media in the steady-state case with strongly separated frequencies and neglecting molecular diffusion. Three-frequency radiation is used as an example in a comparison with the results obtained neglecting interference of counterpropagating waves.

Christian Kraglund Andersen, Klaus Mølmer

A superconducting quantum interference device (SQUID) inserted in a superconducting waveguide resonator imposes current and voltage boundary conditions that makes it suitable as a tuning element for the resonator modes. If such a SQUID element is subject to a periodically varying magnetic flux, the resonator modes acquire frequency sidebands. In this work we calculate the multifrequency eigenmodes of resonators coupled to periodically driven SQUIDs and we use the Lagrange formalism to propose a theory for their quantization. The elementary excitations of a multifrequency mode can couple resonantly to physical systems with different transition frequencies and this makes the resonator an efficient quantum bus for state transfer and coherent quantum operations in hybrid quantum systems. As an example of the application of our multifrequency modes, we determine their coupling to transmon qubits with different frequencies and we present a bichromatic scheme for entanglement and gate operations.

Vladimir I. Osherov

Edmond Geneux, Georges J. Béné, J. Perrenoud