"White and his team fired a powerful laser at a 50-nanometre thick sheet of gold for 45 quadrillionths of a second..."
As a rank amateur I don't understand the other discussions here, but my thinking is that if a material is heated up for such a short period of time, and also only in a very small location ("The laser was focused to a spot approximately 100 µm in radius"), not across the whole mass, then the energy will dissipate across the mass of the material without building up enough to break the bonds and melt.
For me, what'd be more significant to know is how long it'd take for melting to occur/what's the tipping point.
So I've skimmed through the journal article and:
https://www.nature.com/articles/s41586-025-09253-y
"Notably, the temperatures exceed the proposed limit of 3Tm in both cases for over 2 ps. This time is approximately an order of magnitude longer than the characteristic phonon oscillation period and, thus, much longer than required for homogeneous melting"
So the gold did melt, just not instantaneously!
"Our experimental findings raise an important question about the ultimate stability limit for superheating."
Right so both news articles avoid stating that melting occured so far as to suggest it didn't and that was what was significant...oh well, reading the journal article was interesting at least!
One question of mine I didn't see was answered is, what significance do the xrays have on the temperature and time taken to melting?
Thanks for that, much appreciated :)