Abstract

Strong resonant light-matter coupling in a cavity setting is an essential ingredient in fundamental cavity quantum electrodynamics (QED) studies as well as in cavity-QED-based quantum information processing. In particular, a variety of solid-state cavity QED systems have recently been examined, not only for the purpose of developing scalable quantum technologies, but also for exploring novel many-body effects inherent to condensed matter. For example, collective N^1/2-fold enhancement of light-matter coupling in an N-body system, combined with colossal dipole moments available in solids, compared to traditional atomic systems, is promising for entering uncharted regimes of ultrastrong light-matter coupling. Nonintuitive quantum phenomena can occur in such regimes, including a squeezed vacuum state, the Dicke superradiant phase transition, the breakdown of the Purcell effect, and quantum vacuum radiation induced by the dynamic Casimir effect. However, creating a system that combines a long electronic coherence time, a large dipole moment, and a high cavity quality (Q) factor has been a challenging goal.

© 2017 Japan Society of Applied Physics, Optical Society of America