Strongly interacting photons

Optical photons essentially don't interact in vacuum. We wondered what if they did? Our group played a key role in the engineering, understanding, control, and implementation of strongly interacting photons, which led to our theoretical and experimental demonstrations of their numerous applications in optical information processing and to our discoveries of fascinating few-body physics (such as binding of photons into poly-photonic molecules) and many-body physics. Much more remains to be understood and discovered.