Emergent electromagnetism in solids

TL;DR

This paper explores how electromagnetic fields are fundamental to condensed matter physics, highlighting emergent electromagnetic phenomena arising from electronic wavefunctions and their significance in various condensed-matter systems.

Contribution

It provides a comprehensive overview of emergent electromagnetic fields in solids, emphasizing their fundamental role and recent applications in condensed-matter physics.

Findings

Emergent electromagnetic fields arise from electronic wavefunctions.

EEMFs are crucial in phenomena like the quantum Hall effect.

Applications include understanding strongly correlated electrons.

Abstract

Electromagnetic field (EMF) is the most fundamental field in condensed-matter physics. Interaction between electrons, electron-ion interaction, and ion-ion interaction are all of the electromagnetic origin, while the other 3 fundamental forces, i.e., gravitational force, weak and strong interactions are irrelevant in the energy/length scales of condensed-matter physics. Also the physical properties of condensed-matters such as transport, optical, magnetic and dielectric properties, are almost described as their electromagnetic responses. In addition to this EMF in the low energy sector, it often happens that the gauge fields appear as the emergent phenomenon due to the projection of the electronic wavefunctions onto the curved manifold of the Hilbert sub-space. These emergent electromagnetic fields (EEMF's) play important roles in many places in condensed-matter physics including the quantum Hall effect, strongly correlated electrons, and also in non-interacting electron systems. In this article, we describe its fundamental idea and some of the applications recently studied.