Excitement about light–matter coupling results, tempered by lack of agreed-upon mechanism and difficulties reproducing results
Earlier this year, a team of chemists created extraordinary electrical conductance in polystyrene, a usually non-conducting polymer, without altering its chemical makeup. Another group lowered the melting temperature of DNA so that it could fold into ‘origami’ structures at lower temperatures – again, without changing the molecules’ structure. And yet another research team managed to decrease the polarity of long-chained alcohol solvents without chemical modification.
Behind these astonishing results is a seemingly simple setup: a small box, only a few micrometres wide, with mirrored walls. In this optical cavity molecules behave strangely: reactions can be sped up or slowed down, product distributions can be altered, polarity or electrical conductivity changed. The cavity allows scientists to tap into the power of the vacuum field, the transient quantum fluctuations that are baked into the makeup of the universe.
But there’s still no consensus on the mechanism behind the phenomenon and no way to predict which reactions are susceptible to the vacuum field’s influence. This, combined with failures to reproduce a number of results, has made some researchers sceptical that the cavity’s effect on chemical reactivity is real at all. Researchers are now trying to bridge the gap between theory and experiment to understand what is really going on in a cavity.