We report on the noise of a lumped element Direct Current Superconducting Quantum Interference Device amplifier. We show that the noise temperature in the 4 GHz-8 GHz range over ranges of 10's of MHz is below 1 kelvin (three photons of added noise), characterize the overall behavior of the noise as a function of bias parameters, and discuss potential mechanisms which determine the noise performance in this amplifier. We show that this device can provide more than a factor of 10 improvement in practical system noise over existing phase-preserving microwave measurement systems in this frequency band.
@article{arxiv.1009.4673,
title = {Noise Performance of Lumped Element Direct Current Superconducting Quantum Interference Device Amplifiers in the 4 GHz-8 GHz Range},
author = {Lafe Spietz and Kent Irwin and Minhyea Lee and Jose Aumentado},
journal= {arXiv preprint arXiv:1009.4673},
year = {2015}
}