Title: A New Paradigm for Materials Design: Cavity Quantum Electrodynamics (QEDFT)
Abstract: Cavity materials engineering is an emerging field at the intersection of quantum optics and condensed matter physics, where the quantum vacuum fluctuations of confined electromagnetic fields are harnessed to control and design material properties at equilibrium. By embedding quantum materials inside optical cavities, it becomes possible to enhance light–matter coupling to the point where even the vacuum field can induce macroscopic changes—such as shifts in superconductivity, magnetism, or structural phases—without relying on external driving or photon excitation. This “dark” regime fundamentally differs from traditional light-driven approaches and opens a new path for modifying the ground state of materials.
To accurately describe these phenomena, new theoretical frameworks beyond standard approaches are required. One such framework is Quantum Electrodynamical Density Functional Theory (QEDFT), which incorporates quantized electromagnetic fields directly into electronic structure theory, enabling first-principles simulations of equilibrium light–matter interactions. We review the key theoretical developments in this area, with a focus on ab initio methods, and survey recent experimental breakthroughs demonstrating how optical cavities can reshape material behavior. Finally, we discuss outstanding challenges and future directions for this promising approach to quantum materials design driven by vacuum fluctuations rather than classical light.