Obviously they didn’t, but does anyone here understand what was actually done (or claimed to be done) here, and why this metaphor (presumably that is what it is) is evenremotely appropriate (if it is)?
The argument seems to be that a certain type of light ray shone through a certain ferromagnetic fluid emulate to a certain extent the world lines of particles (i.e. the path they trace out) in 2+1 D (two space, one time) flat spacetime when a strong enough magnetic field is applied
By applying a magnetic field to the fluid that is almost, but not quite, strong enough to produce this behaviour, random fluctuations will mean that regions of the fluid will exhibit this behaviour temporarily mimicking spacetimes popping in and out of existence in a multiverse the authors of the paper claim.
Much less impressive than the headline in the article.
Does it have any implications for cosmology? For anything much at all?
Also, I would like to understand whether the hyperbole is the entirely the fault of the journalist, or are the scientists responsible too? Is this the normal way of talking about this type of phenomenon in the relevant field?
It almost certainly doesn’t have any implications for cosmology at all and the authors don’t claim it does. All it really is is a physical emulation of a toy cosmological model.
The popular science press can be extremely hyperbolic (no pun intended - the paper is about the properties of a hyperbolic metamaterial), but so can scientists sometimes. When the two combine it can lead. The paper (which is linked to at the bottom of the article) doesn’t make any claims as to the likely usefulness of its results, but you have to wonder if by calling the paper Experimental Demonstration of a Metamaterial “Multiverse” in a Ferrofluid they might’ve been hoping to attract a bit of attention.