BCS theory

BCS theory explains how conventional superconductors conduct electricity without resistance. It describes how, at very low temperatures, electrons pair up into "Cooper pairs" through interactions with the material's atomic vibrations (phonons). These pairs move coherently through the lattice, avoiding scattering that causes resistance. The formation of Cooper pairs creates an energy gap, preventing energy loss. This collective behavior results in the zero-resistance, perfect conductivity characteristic of superconductors, making BCS theory a fundamental explanation for classical superconductivity observed in many materials.