Solid-state qubit measurement with single electron transistors

In this paper we consider the continuous weak measurement of a solid-state qubit by single electron transistors (SET). For single-dot SET, we find that in nonlinear response regime the signal-to-noise ratio can violate the universal upper bound imposed quantum mechanically on any linear response detectors. We understand the violation by means of the cross-correlation of the detector currents. For double-dot SET, we discuss its robustness against wider range of temperatures, quantum efficiency, and the relevant open issues unresolved.

In this paper we consider the continuous weak measurement of a solid-state qubit by single electron transistors (SET). For single-dot SET, we find that in nonlinear response regime the signal-to-noise ratio can violate the universal upper bound imposed quantum mechanically on any linear response detectors. We understand the violation by means of the cross-correlation of the detector currents. For double-dot SET, we discuss its robustness against wider range of temperatures, quantum efficiency, and the relevant open issues unresolved.

zhangdi于2010-03-09批量导入

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Natl Sci Council.; Natl Ctr Theoret Sci S.; Natl Ctr Theoret Sci N.; Acad Sinica, Res Ctr Appl Sci.; Natl Cheng Kung Univ.; Ctr Theoret Sci.; Natl Taiwan Univ, Dept Phys.; Natl Taiwan Univ, Coll Sci.

[Jiao, HuJun; Li, Feng; Li, Xin-Qi] Chinese Acad Sci, Inst Semicond, State Key Lab Superlattices & Microstruct, Beijing 100083, Peoples R China

Natl Sci Council.; Natl Ctr Theoret Sci S.; Natl Ctr Theoret Sci N.; Acad Sinica, Res Ctr Appl Sci.; Natl Cheng Kung Univ.; Ctr Theoret Sci.; Natl Taiwan Univ, Dept Phys.; Natl Taiwan Univ, Coll Sci.