标题： 连续测量电荷量子比特在任意偏置下的点接触探测器：非弹性隧穿的作用 显示英文标题

标题： Continuous measurement of a charge qubit with a point contact detector at arbitrary bias: the role of inelastic tunnelling

摘要： 我们研究了一个电荷量子比特的动力学，该量子比特由双势阱中的一个电子组成，并使用量子轨迹形式主义与点接触（PC）探测器耦合。 与之前的工作不同，我们的分析适用于PC上的任意源-漏偏置，但仅限于亚佐诺极限。 我们发现，PC中的非弹性隧穿过程对动力学有显著影响。 这些过程降低了PC作为量子比特读出设备的效率，并且即使在源-漏偏置为零时也会引起弛豫。 我们表明，亚佐诺动力学分为两个区域：低偏置和高偏置，在这两个区域中，PC电流和电流功率谱表现出明显不同的行为。 为了进一步说明这两个区域之间的区分以及探测器的低效性，我们展示了条件量子比特和探测器动力学的模拟量子轨迹。 我们还描述了如何在亚佐诺区域内实现任意基下的单次测量。 显示英文摘要

摘要： We study the dynamics of a charge qubit, consisting of a single electron in a double well potential, coupled to a point-contact (PC) electrometer using the quantum trajectories formalism. In contrast with previous work, our analysis is valid for arbitrary source-drain bias across the PC, but is restricted to the sub-Zeno limit. We find that the dynamics is strongly affected by inelastic tunnelling processes in the PC. These processes reduce the efficiency of the PC as a qubit readout device, and induce relaxation even when the source-drain bias is zero. We show that the sub-Zeno dynamics are divided into two regimes: low- and high-bias in which the PC current and current power spectra show markedly different behaviour. To further illustrate the division between the regimes and the inefficiency of the detector, we present simulated quantum trajectories of the conditional qubit and detector dynamics. We also describe how single shot measurements in an arbitrary basis may be achieved in the sub-Zeno regime.