Oberholzer S, Sukhorukov E V, Schönenberger C
Institut für Physik, Universität Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
Nature. 2002 Feb 14;415(6873):765-7. doi: 10.1038/415765a.
The discreteness of charge in units of e led Schottky in 1918 to predict that the electrical current in a vacuum tube fluctuates even if all spurious noise sources are eliminated carefully. This phenomenon is now widely known as shot noise. In recent years, shot noise in mesoscopic conductors, where charge motion is quantum-coherent over distances comparable to the system size, has been studied extensively. In those experiments, charge does not propagate as an isolated entity through free space, as for vacuum tubes, but is part of a degenerate and quantum-coherent Fermi sea of charges. It has been predicted that shot noise in mesoscopic conductors can disappear altogether when the system is tuned to a regime where electron motion becomes classically chaotic. Here we experimentally verify this prediction by using chaotic cavities where the time that electrons dwell inside can be tuned. Shot noise is present for large dwell times, where the electron motion through the cavity is 'smeared' by quantum scattering, and it disappears for short dwell times, when the motion becomes classically deterministic.
电荷以e为单位的离散性使得肖特基在1918年预测，即使仔细消除所有杂散噪声源，真空管中的电流仍会波动。这种现象现在被广泛称为散粒噪声。近年来，人们对介观导体中的散粒噪声进行了广泛研究，在介观导体中，电荷运动在与系统尺寸相当的距离上是量子相干的。在这些实验中，电荷不像在真空管中那样作为一个孤立的实体在自由空间中传播，而是简并且量子相干的费米电荷海的一部分。据预测，当系统被调谐到电子运动变为经典混沌的状态时，介观导体中的散粒噪声会完全消失。在这里，我们通过使用可以调节电子在其中停留时间的混沌腔，通过实验验证了这一预测。对于较长的停留时间，散粒噪声存在，此时电子通过腔的运动被量子散射“涂抹”，而对于较短的停留时间，当运动变为经典确定性时，散粒噪声消失。
