Period multiplication in a parametrically driven superconducting resonator

Artikel i vetenskaplig tidskrift, 2018

We report on the experimental observation of period multiplication in parametrically driven tunable superconducting resonators. We modulate the magnetic flux through a superconducting quantum interference device, attached to a quarter-wavelength resonator, with frequencies nω close to multiples, n = 2, 3, 4, and 5, of the resonator fundamental mode and observe intense output radiation at ω. The output field manifests n-fold degeneracy with respect to the phase, and the n states are phase shifted by 2π/n with respect to each other. Our demonstration verifies the theoretical prediction by Guo et al. [Phys. Rev. Lett. 111, 205303 (2013)] and paves the way for engineering complex macroscopic quantum cat states with microwave photons.