We present the first experimental realization of a widely frequency tunable, non-degenerate three-wave mixing device for quantum signals at GHz frequency. It is based on a new superconducting building-block consisting of a ring of four Josephson junctions shunted by a cross of four linear inductances. The phase configuration of the ring remains unique over a wide range of magnetic fluxes threading the loop. It is thus possible to vary the inductance of the ring with flux while retaining a strong, dissipation-free, and noiseless non-linearity. The device has been operated in amplifier mode and its noise performance has been evaluated by using the noise spectrum emitted by a voltage biased tunnel junction at finite frequency as a test signal. The unprecedented accuracy with which the crossover between zero-point-fluctuations and shot noise has been measured provides an upper-bound for the noise and dissipation intrinsic to the device.
@article{arxiv.1202.1315,
title = {Widely tunable, non-degenerate three-wave mixing microwave device operating near the quantum limit},
author = {Nicolas Roch and Emmanuel Flurin and François Nguyen and Pascal Morfin and Philippe Campagne-Ibarcq and Michel H. Devoret and Benjamin Huard},
journal= {arXiv preprint arXiv:1202.1315},
year = {2012}
}
Comments
Accepted for Physical Review Letters. Supplementary material can be found in the source package