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arXiv 0802.4042cond-mat.mes-hall
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非高斯噪声的约瑟夫森结探测器

Josephson junction detector of non-Gaussian noise

Hermann Grabert

摘要:

从理论上研究了利用约瑟夫森结作为片上探测器测量非线性介观导体电流噪声的高阶累积量。该文件解决的制度,介观导体的噪声启动激活逃逸的约瑟夫森检测器的零电压状态,这可以被观察到的电压上升。结果表明,从约翰逊-奈奎斯特噪声的偏差可以主要占由一个有效的温度,这取决于第二噪声累积量的导体。从高斯统计的偏差导致相当弱的影响,基本上只有第三累积量可以利用从零电压状态的逃逸率的偏置电流的方向上的校正的依赖性进行测量。当偏置电流接近临界电流时,这些修正消失。该理论是基于一个描述的不可逆过程和波动的状态变量和共轭力。这种方法,回到Onsager和Machlup的工作,扩展到非高斯噪声,它示出的共轭力的电荷起着类似的作用,在最近的方法来描述非高斯噪声统计的计数字段。该理论允许获得渐近精确的结果逃逸率在弱噪声限制的约瑟夫森检测器的阻尼强度的所有值。同样,通过平等对待两个耦合的介观器件,充分考虑了检测器对噪声产生导体的反馈。

英文摘要:

The measurement of higher order cumulants of the current noise generated by a nonlinear mesoscopic conductor using a Josephson junction as on-chip detector is investigated theoretically. The paper addresses the regime where the noise of the mesoscopic conductor initiates activated escape of the Josephson detector out of the zero-voltage state, which can be observed as a voltage rise. It is shown that the deviations from Johnson-Nyquist noise can mostly be accounted for by an effective temperature which depends on the second noise cumulant of the conductor. The deviations from Gaussian statistics lead to rather weak effects and essentially only the third cumulant can be measured exploiting the dependence of the corrections to the rate of escape from the zero-voltage state on the direction of the bias current. These corrections vanish as the bias current approaches the critical current. The theory is based on a description of irreversible processes and fluctuations in terms of state variables and conjugate forces. This approach, going back to work by Onsager and Machlup, is extended to account for non-Gaussian noise, and it is shown that the thermodynamically conjugate force to the electric charge plays a role similar to the counting field introduced in more recent approaches to describe non-Gaussian noise statistics. The theory allows to obtain asymptotically exact results for the rate of escape in the weak noise limit for all values of the damping strength of the Josephson detector. Also the feedback of the detector on the noise generating conductor is fully taken into account by treating both coupled mesoscopic devices on an equal footing.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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