Nonlinear amplifiers such as the transistor are ubiquitous in classical technology, but their quantum analogues are not well understood. We introduce a class of nonlinear amplifiers that amplify any normal operator and add only a half-quantum of vacuum noise at the output. In the large-gain limit, when used in conjunction with a noisy linear detector, these amplifiers implement ideal measurements of the normal operator.
@article{arxiv.2010.13851,
title = {Quantum limits on noise for a class of nonlinear amplifiers},
author = {Jeffrey M. Epstein and K. Birgitta Whaley and Joshua Combes},
journal= {arXiv preprint arXiv:2010.13851},
year = {2021}
}
Comments
8 pages + appendix. V2 ~ published version, including a new section on three mode amplifiers for measuring normal operators