title: Direct measurement on the geometric phase of a double quantum dot qubit via quantum point contact device.
abstract: We propose a direct measurement scheme to read out the geometric phase of a coupled double quantum dot system via a quantum point contact(QPC) device. An effective expression of the geometric phase has been derived, which relates the geometric phase of the double quantum dot qubit to the current through QPC device. All the parameters in our expression are measurable or tunable in experiment. Moreover, since the measurement process affects the state of the qubit slightly, the geometric phase can be protected. The feasibility of the scheme has been analyzed. Further, as an example, we simulate the geometrical phase of a qubit when the QPC device is replaced by a single electron transistor(SET).
authors.affiliation: Beijing Computational Science Research Center (CSRC), Beijing 100094, China.
authors.forename: Bao
authors.initials: B
authors.lastname: Liu
authors.affiliation: School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China.
authors.forename: Feng-Yang
authors.initials: FY
authors.lastname: Zhang
authors.affiliation: Department of Physics, Harbin Institute of Technology, Harbin, 150001, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.affiliation: School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: He-Shan
authors.initials: HS
authors.lastname: Song