Quantum coherent feedback has been proven to be an efficient way to tune the dynamics of quantum optical systems and, recently, those of solid-state quantum circuits. Here, inspired by the recent progress of quantum feedback experiments, especially those in mesoscopic circuits, we prove that superconducting circuit QED systems, shunted with a coherent feedback loop, can change the dynamics of a superconducting transmission line resonator, i.e., a linear quantum cavity, and lead to strong on-chip nonlinear optical phenomena. We find that bistability can occur under the semiclassical approximation, and photon anti-bunching can be shown in the quantum regime. Our study presents new perspectives for engineering nonlinear quantum dynamics on a chip.
@article{arxiv.1309.3208,
title = {Feedback-induced nonlinearity and superconducting on-chip quantum optics},
author = {Zhong-Peng Liu and Hui Wang and Jing Zhang and Yu-xi Liu and Re-Bing Wu and Franco Nori},
journal= {arXiv preprint arXiv:1309.3208},
year = {2014}
}