I like this explanation. I've found that frame dragging (https://en.wikipedia.org/wiki/Frame-dragging) completes this intuition. In a hypothetical reference frame where the universe is rotating around the bucket, the effect of the rotating mass "drags" space-time such that the geodesics are curved and the water experiences an outward "force".
The way I understand it, frame-dragging is negligible if, as in your example, the bucket is by itself in deep space, far away from any massive object. Frame-dragging affects the nearby space around a rotating massive object (that induces a strong gravitational field). The mass of the water is very small and induces an extremely weak gravitational field, so even though it's rotating, its frame-dragging would be exceedingly small. Likewise, the gravitational influence (and consequently, any frame-dragging effect) of the rest of the universe on the bucket is very close to zero, owing to the extreme distances involved.
My understanding is that in the case of an extremely massive object, frame dragging leads to local changes in spacetime that amount to "changing" what the "background" reference frame looks like? If the bucket were truly massive it would indeed start to look a little bit like space were rotating around the bucket, and not the other way around? Since the bucket is of negligible mass, of course, it is the mass of the rest of the universe that "sets" the reference frame. This is my layperson's understanding. For me the important point is that it is the global arrangement of mass in the universe that determines the reference frame. Conceptually, I find it helpful to think that, indeed, you can make the universe spin around the bucket, if your bucket contains a fair portion of the mass in the universe? Perhaps I have misunderstood something, however.
They examine a quasiparticle, so its "mass" is a number describing the behavior of an emergent excitation of the semiconductor. It's not actually mass in the sense of an elementary particle.
