We study the dynamic sensitivity of the quantum Rabi model, which exhibits quantum criticality in the finite-component-system case. This dynamic sensitivity can be detected by introducing an auxiliary two-level atom far-off-resonantly coupled to the cavity field of the quantum Rabi model. We find that when the quantum Rabi model goes through the critical point, the auxiliary atom experiences a sudden decoherence, which can be characterised by a sharp decay of the Loschmidt echo. Our scheme will provide a reliable way to observe quantum phase transition in ultrastrongly coupled quantum systems.
Cite
@article{arxiv.2101.01504,
title = {Dynamic sensitivity of quantum Rabi model with quantum criticality},
author = {Ying Hu and Jian Huang and Jin-Feng Huang and Qiong-Tao Xie and Jie-Qiao Liao},
journal= {arXiv preprint arXiv:2101.01504},
year = {2021}
}