Multiphoton transitions in a macroscopic quantum two-state system
arXiv:cond-mat/0403425 · doi:10.1103/PhysRevLett.93.037001
Abstract
We have observed multiphoton transitions between two macroscopic quantum-mechanical superposition states formed by two opposite circulating currents in a superconducting loop with three Josephson junctions. Resonant peaks and dips of up to three-photon transitions were observed in spectroscopic measurements when the system was irradiated with a strong RF-photon field. The widths of the multiphoton absorption dips are shown to scale with the Bessel functions in agreement with theoretical predictions derived from the Bloch equation or from a spin-boson model.
4 pages, 3 figures