High fidelity single shot qubit state readout is essential for many quantum information processing protocols. In superconducting quantum circuit, the qubit state is usually determined by detecting the dispersive frequ...High fidelity single shot qubit state readout is essential for many quantum information processing protocols. In superconducting quantum circuit, the qubit state is usually determined by detecting the dispersive frequency shift of a microwave cavity from either transmission or reflection. We demonstrate the use of constructive interference between the transmitted and reflected signal to optimize the qubit state readout, with which we find a better resolved state discrimination and an improved qubit readout fidelity. As a simple and convenient approach, our scheme can be combined with other qubit readout methods based on the discrimination of cavity photon states to further improve the qubit state readout.展开更多
The electronic Fabry–Pérot interferometer operating in the quantum Hall regime may be a promising tool for probing edge state interferences and studying the non-Abelian statistics of fractionally charged quasipa...The electronic Fabry–Pérot interferometer operating in the quantum Hall regime may be a promising tool for probing edge state interferences and studying the non-Abelian statistics of fractionally charged quasiparticles. Here we report on realizing a quantum Hall Fabry–Pérot interferometer based on monolayer graphene. We observe resistance oscillations as a function of perpendicular magnetic field and gate voltage both on the electron and hole sides. Their Coulomb-dominated origin is revealed by the positive(negative) slope of the constant phase lines in the plane of magnetic field and gate voltage on the electron(hole) side. Our work demonstrates that the graphene interferometer is feasible and paves the way for the studies of edge state interferences since high-Landau-level and even denominator fractional quantum Hall states have been found in graphene.展开更多
基金Supported by the Beijing Academy of Quantum Information Sciencethe Frontier Science Center for Quantum Information of the Ministry of Education of China through the Tsinghua University Initiative Scientific Research Program+3 种基金the National Natural Science Foundation of China (Grant No. 11874235)the National Key Research and Development Program of China (Grant Nos. 2016YFA0301902 and 2020YFA0309500)support from Shuimu Tsinghua Scholar Programthe International Postdoctoral Exchange Fellowship Program。
文摘High fidelity single shot qubit state readout is essential for many quantum information processing protocols. In superconducting quantum circuit, the qubit state is usually determined by detecting the dispersive frequency shift of a microwave cavity from either transmission or reflection. We demonstrate the use of constructive interference between the transmitted and reflected signal to optimize the qubit state readout, with which we find a better resolved state discrimination and an improved qubit readout fidelity. As a simple and convenient approach, our scheme can be combined with other qubit readout methods based on the discrimination of cavity photon states to further improve the qubit state readout.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0300601 and 2017YFA0303304)the National Natural Science Foundation of China(Grant Nos.11874071,11774005,and 11974026)Beijing Academy of Quantum Information Sciences,China(Grant No.Y18G22)
文摘The electronic Fabry–Pérot interferometer operating in the quantum Hall regime may be a promising tool for probing edge state interferences and studying the non-Abelian statistics of fractionally charged quasiparticles. Here we report on realizing a quantum Hall Fabry–Pérot interferometer based on monolayer graphene. We observe resistance oscillations as a function of perpendicular magnetic field and gate voltage both on the electron and hole sides. Their Coulomb-dominated origin is revealed by the positive(negative) slope of the constant phase lines in the plane of magnetic field and gate voltage on the electron(hole) side. Our work demonstrates that the graphene interferometer is feasible and paves the way for the studies of edge state interferences since high-Landau-level and even denominator fractional quantum Hall states have been found in graphene.
