We've seen particles that are massless only when moving one direction
We've seen particles that are massless only when moving one direction
Inside a hunk of a material called a semimetal, scientists have uncovered signatures of bizarre particles that sometimes move like they have no mass, but at other times move just like a very massive particle
The particles are "semi-Dirac fermions":
Instead of moving forwards in a kind of river of electric current, [the electrons] began to trace out circular trajectories, like eddies in that river. And because they were so cold, they were also susceptible to quantum effects, meaning each acted like a wave that self-reinforced as it flowed around the eddy. These behaviours caused the semi-Dirac fermions to emerge.
Not exactly sure what a "semi-Dirac fermion" is, but it seems like another case of electrons doing weird sh*t at low temperatures.
paywalled
Here's the study: https://arxiv.org/abs/2311.03735