We investigate the dephasing mechanisms induced by the charge noise and microwave heating effect acting on a graphene double quantum dot （DQD） capacitively coupled to a microwave resonator. The charge noise is obtai...We investigate the dephasing mechanisms induced by the charge noise and microwave heating effect acting on a graphene double quantum dot （DQD） capacitively coupled to a microwave resonator. The charge noise is obtained from DC transport current, and its contribution to dephasing is simultaneously determined by the amplitude response of the microwave resonator. A lowfrequency 1/f-type noise is demonstrated to be the dominant factor of the dephasing of graphene DQD. Furthermore, when the applied microwave power is larger than -90 dBm, the dephasing rate of graphene DQD increases rapidly with the increase of microwave power, and fluctuates slightly with the applied microwave power smaller than -90 dBm. Our results can be applied to suppress the impeditive influence on the dephasing of graphene-based devices associated with microwave input in the perspective investigations.展开更多
This research presents the development of HL-2A neutron yield measurement which includes^(235)U fission chamber and BF_(3)and^(3)He proportional counters.Equivalent noise formula of the radiation detection signal ampl...This research presents the development of HL-2A neutron yield measurement which includes^(235)U fission chamber and BF_(3)and^(3)He proportional counters.Equivalent noise formula of the radiation detection signal amplification system was derived to guide the development of the signal amplification system.Then all detectors were calibrated in situ by using the^(252)C_(f)neutron source.The neutron yield of the HL-2A during neutral beam heating was analyzed.These results indicate that the developed neutron flux diagnostic system can obtain neutron yield results under various experimental conditions of the HL-2A tokamak,and can provide information on neutron yield.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0301700)the National Natural Science Foundation of China(Grant Nos.61674132,11674300,11575172,and 11625419)the Anhui Initiative in Quantum information Technologies,China(Grant No.AHY080000)
文摘We investigate the dephasing mechanisms induced by the charge noise and microwave heating effect acting on a graphene double quantum dot （DQD） capacitively coupled to a microwave resonator. The charge noise is obtained from DC transport current, and its contribution to dephasing is simultaneously determined by the amplitude response of the microwave resonator. A lowfrequency 1/f-type noise is demonstrated to be the dominant factor of the dephasing of graphene DQD. Furthermore, when the applied microwave power is larger than -90 dBm, the dephasing rate of graphene DQD increases rapidly with the increase of microwave power, and fluctuates slightly with the applied microwave power smaller than -90 dBm. Our results can be applied to suppress the impeditive influence on the dephasing of graphene-based devices associated with microwave input in the perspective investigations.
基金partially supported by the Science&Technology Department of Sichuan Province in China (No.2021YFSY0018)National Natural Science Foundation of China (No.11675049).
文摘This research presents the development of HL-2A neutron yield measurement which includes^(235)U fission chamber and BF_(3)and^(3)He proportional counters.Equivalent noise formula of the radiation detection signal amplification system was derived to guide the development of the signal amplification system.Then all detectors were calibrated in situ by using the^(252)C_(f)neutron source.The neutron yield of the HL-2A during neutral beam heating was analyzed.These results indicate that the developed neutron flux diagnostic system can obtain neutron yield results under various experimental conditions of the HL-2A tokamak,and can provide information on neutron yield.
