Controlling fluctuations in small structures: Hidden information in the noise

Due to thermal and quantum fluctuations the charge density and the electromagnetic field in metallic structures possess randomly changing components, which control the signal to noise ratio in sensors. With the emergence of nanotechnology individual sensors are made with smaller and smaller structures. We calculated and measured the spatial distribution of the mean-square value of the local fluctuation of the charge density and the electromagnetic field in micrometer-size metallic circular and triangular films and found that the spatial distribution of the fluctuation is not uniform; the magnitude of the fluctuation at a fixed frequency can change abruptly by an order of magnitude as the size of the structure is changed. This previously unanticipated result provides for understanding of fundamental physics and help improve the design of devices.

Automated summary

The study revealed that the charge density and electromagnetic field in metallic structures have randomly changing components, affecting the signal to noise ratio in sensors, with the development of nanotechnology leading to smaller sensors. The non-uniform spatial distribution of fluctuations and abrupt changes in magnitude as structure size varies were unexpected findings that provide insights into fundamental physics and can aid in device design improvements.