Understanding the Branly effect

TL;DR

This paper explores the historical Branly effect, where metallic granular conductors drastically reduce resistance under electromagnetic excitation, and proposes a new explanation linking it to induced tunnelling phenomena.

Contribution

The paper introduces a novel interpretation of the Branly effect by connecting it to induced tunnelling, providing a potential physical explanation for the long-standing phenomenon.

Findings

Links the Branly effect to induced tunnelling.

Provides a theoretical framework for the effect.

Suggests new avenues for granular material research.

Abstract

At the end of the nineteenth century \'{E}douard Branly discovered that the electrical resistance of a granular metallic conductor could drop by several orders of magnitude when excited by the electromagnetic field emitted by an electrical spark. Despite the fact that this effect has been used to detect radio waves in the early times of wireless telegraphy and more recently studied in the field of granular materials, no satisfactory explanation of the physical origin of the effect has been given yet. In this contribution we propose to relate the Branly effect to the induced tunnelling effect first described by Fran\c{c}ois Bardou and Dominique Boos\'{e}.