Quantum feedback amplification
Abstract
Quantum amplification is essential for various quantum technologies such as communication and weak-signal detection. However, its practical use is still limited due to inevitable device fragility that brings about distortion in the output signal or state. This paper presents a general theory that solves this critical issue. The key idea is simple and easy to implement: just a passive feedback of the amplifier's auxiliary mode, which is usually thrown away. In fact, this scheme makes the controlled amplifier significantly robust, and furthermore it realizes the minimum-noise amplification even under realistic imperfections. Hence, the presented theory enables the quantum amplification to be implemented at a practical level. Also, a nondegenerate parametric amplifier subjected to a special detuning is proposed to show that, additionally, it has a broadband nature.
Cite
@article{arxiv.1508.03708,
title = {Quantum feedback amplification},
author = {Naoki Yamamoto},
journal= {arXiv preprint arXiv:1508.03708},
year = {2016}
}
Comments
11 pages