Observation of the exceptional point in superconducting qubit with dissipation controlled by parametric modulation  

作　　者：Zhan Wang Zhongcheng Xiang Tong Liu Xiaohui Song Pengtao Song Xueyi Guo Luhong Su He Zhang Yanjing Du Dongning Zheng 王战;相忠诚;刘桐;宋小会;宋鹏涛;郭学仪;苏鹭红;张贺;杜燕京;郑东宁(Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;China University of Geosciences,Beijing 100083,China)

机构地区：[1]Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Songshan Lake Materials Laboratory,Dongguan 523808,China [4]China University of Geosciences,Beijing 100083,China

出　　处：《Chinese Physics B》2021年第10期66-72,共7页中国物理B（英文版）

基　　金：supported by the State Key Development Program for Basic Research of China(Grant Nos.2017YFA0304300 and 2016YFA0300600);the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2020B0303030001);the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000).

摘　　要：Open physical systems described by the non-Hermitian Hamiltonian with parity-time-reversal(PT)symmetry show peculiar phenomena,such as the presence of an exceptional point(EP)at which the PT symmetry is broken and two resonant modes of the Hamiltonian become degenerate.Near the EP,the system could be more sensitive to external perturbations and this may lead to enhanced sensing.In this paper,we present experimental results on the observation of PT symmetry broken transition and the EP using a tunable superconducting qubit.The quantum system of investigation is formed by the two levels of the qubit and the energy loss of the system to the environment is controlled by a method of parametric modulation of the qubit frequency.This method is simple with no requirements for additional elements or qubit device modifications.We believe it can be easily implemented on multi-qubit devices that would be suitable for further exploration of non-Hermitian physics in more complex and diverse systems.

关 键 词：exceptional point parity-time-reversal(PT)symmetry longitudinal field modulation 

分 类 号：O413[理学—理论物理]