Physical Review Letters has recently published a research article on the universal dissipationless dynamics of Gaussian continuous-variable (CV) systems in the presence of a band-gapped bosonic environment (see Fig.1).
The research was jointly conducted by doctoral student Zhu Hanjie under the guidance of Professor Zhang Guofeng from School of Physics and Nuclear Energy Engineering of Beihang University, researcher Liu Wuming from Institute of Physics, Chinese Academy of Sciences, and Professor Zhuang Lin from School of Physics of Sun Yat-Sen University. Zhu Hanjie and Zhang Guofeng are the joint first authors, with Zhang being the corresponding author.
According to the paper, bound states in CV systems, different from that in finite-dimensional systems, are characterized by localized modes with frequencies embedded in environmental spectral gaps. Environmental band gaps can induce localized modes (see Fig.2), which give rise to the dissipationless dynamics where the system behaves as free oscillators instead of experiencing a full decay in the long-time limit (see Fig. 3).
The complete characterization of localized modes presented shows the existence of the critical system-environment coupling. Beyond the critical values, localized modes can be produced, and the system dynamics become dissipationless.
The novel dynamics can be utilized to overcome the environmental noises and protect the quantum resources in the continuous-variable quantum information. It also provides a clue to understand the non-Markovianity in more general many-body open quantum systems.
Gaussian systems, which constitute a large class of CV systems and play a central role, serve as primary tools in CV quantum information. The dissipation and decoherence processes induced by surroundings are the central topic of study in the theory of open quantum systems. These unavoidable processes almost always lead to the irreversible loss of quantum coherence and quantum correlations, which are the crucial resources for quantum technologies.
This work was supported by the National Natural Science Foundation of China (NSFC), the National Key R&D Program of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, and so on.
Fig.1 Illustration of the general Gaussian system of open oscillators
Fig.2 (a) band-gapped structure of the environment spectrum; (b) distribution of localized state in the system
Fig. 3 Dissipationless dynamics in the system (the average values of the coordinates varying with time)
The article is available at:
Reported by Cai Hongyan
Reviewed by Wang Wenwen
Edited by Jia Aiping and Li Siying
Translated by Li Siying