Charge noise acting on graphene double quantum dots in circuit quantum electrodynamics architecture

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 d Bm, 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 d Bm. 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.     

阳射线研究简史

阳射线研究简史肖明（湖北教育学院物理系，武汉４３００６０）杨建邺（华中理工大学物理系，武汉４３００７４）人们在回顾气体放电研究的历史时，对阴极射线作过详尽的探讨，但对阳射线（ｐｏｓｉｔｉｖｅｒａｙｓ）研究的历史，却很少有人注意，实际上，这段鲜为人知的...     

Probing Energy Spectrum of Quadruple Quantum Dots with Microwave Field

A double quantum dot defines a qubit by a two-level system. The coupling between two qubits induces a double two-level system into a four-level system. We study experimentally the coupling between two capacitive coupled GaAs/AlGaAs double quantum dots while tuning the energy detuning of each double quantum dot simultaneously. Applying microwave photons （at a frequency of 20 GHz） on this system and observing the resonance tunneling with a quantum point contact detector, we obtain an excitation spectrum which is consistent with the numerical simuIation result of a coupled two-qubit Hamiltonian. This study demonstrates that a double quantum dot can be exploited as an extraordinary platform for controlled quantum gates.     

风雨操场建筑基于中震性能设计的抗震分析

目前,我国对风雨操场类建筑结构的设计,是以小震弹性计算结构的内力和变形,再辅之以各种抗震技术措施以考虑大震影响,对于其在中震及大震作用下的抗震性能不够明确.本文以某单层带附属框架的风雨操场小震弹性设计模型为基准,分别进行中震不屈服和中震弹性设计,比较三种设计方法由性能目标不同所引起的构件配筋变化及抗震性能差别.研究认为...     

非绝热消除条件下输出边频量子关联

考虑了双模腔内含有N个三能级V型原子的系综与两个量子化场之间的相互作用。在非绝热消除原子变量的条件下,分析了两个初始为相干态的输入场从腔内输出后的量子关联性质。结果表明在恰当的条件下,在中心频率处可以获得量子纠缠,但随合作参数的增加,中心频率处的纠缠变小甚至消失。与此同时,在高频区间则产生了一对边频量子纠缠。这是由于合作参数增加引起的真空拉比分裂导致了高频处获得量子关联。此外,通过调节量子化场的强度以及原子和场的反对称失谐,还可获得两对边频量子纠缠。这对边频量子关联的研究具有十分重要的价值。