Scientists finally discover the demon particle – why it matters Premium

An elusive particle proposed in 1956 by theoretical physicist David Pines has just been discovered by a team of scientists led by Peter Abbamonte of the University of Illinois. Scientists long suspected that this particle, called a ‘demon’, plays a fundamental role in the characteristics of several metals, but had been unable to confirm its existence thus far.

An elusive particle proposed in 1956 by theoretical physicist David Pines has just been discovered by a team of scientists led by Peter Abbamonte of the University of Illinois.

Scientists long suspected that this particle, called a ‘demon’, plays a fundamental role in the characteristics of several metals, but had been unable to confirm its existence thus far.

“Demons have been theoretically conjectured for a long time, but experimentalists never studied them,” Dr. Abbamonte said of the discovery in a press release. “In fact, we weren’t even looking for it. But it turned out we were doing exactly the right thing, and we found it.”

The demon is not a particle in the conventional sense of the term. Instead, it is a collection of particles, or a composite particle, made of electrons. (Protons are another example of a composite particle; they are made up of quarks.)

From excitation to plasmon

In a solid, electrons can interact to form collective units, or excitations. This possibility was one of the fundamental discoveries in condensed-matter physics. One example of an excitation is a denser group of electrons in one part of the solid relative to another.

If supplied with enough energy, these excitations can form a composite particle called a plasmon.