An elusive "demon" particle has been observed inside a superconductor nearly 70 years after it was first predicted. Its discovery could help resolve the mystery of how superconductors work.
Pines' demon is a transparent, chargeless particle discovered inside a sample of the superconductor strontium ruthenate. It is a plasmon — a ripple across the electrons of a
plasma that behaves much like a particle — meaning it's a quasiparticle.
Theorists think that plasmons may facilitate superconductivity in materials. If physicists are able to find out how, they could use Pines' demon to shed light on
room-temperature superconductors — one of the "holy grails" of physics that would enable near-lossless transmission of electricity. The researchers published their findings Aug. 9 in the journal
Nature.
Related: Did scientists really create a room temperature superconductor? Not so fast, experts say.
"Demons have been theoretically conjectured for a long time, but experimentalists never studied them,"
Peter Abbamonte, a physics professor at the University of Illinois Urbana-Champaign,
said in a statement. "In fact, we weren't even looking for it. But it turned out we were doing exactly the right thing, and we found it."
David Pines first conceived of his demon in 1956, predicting it would emerge inside certain metals when two sets of electrons at different energy bands form two plasmons. If these plasmons fell out of phase with each other, such that the peaks of one line up with the valleys of the other, they could partially cancel out.
