# Q: Laser cooled hydrogen

Is it possible to cool down hydrogen some much (using lasers) to get a metalic form of the element? Or to try to produce it no such cooling is required?

• Low temperature is helpful, but the main thing you need to produce metallic hydrogen is insanely high pressure. See en.wikipedia.org/wiki/… – PM 2Ring Feb 12 '17 at 13:08

Laser cooling of atomic samples, which allows for temperature as low as few $nK$ is performed on gaseous samples. This is the condition for having a clean way to address a transition with a laser - the samples is essentially many times one single atom, which can be addressed with the many times one photon that constitute the laser. In solid state, interatomic interactions changes a lot the way you can play with atoms.
This means that cold atom experiments take place at very low densities (typically $10^{15}$ cm$^{-3}$). So there is no laser cooling of atomic hydrogen into metallic state, it is incompatible with the technique itself.