The first mentions to this type of matter appeared half a century ago, but only now has its existence been confirmed.
A group of physicists from the University of Illinois at Urbana-Champaign (USA) have announced the discovery of a new state of matter: excitonium, according to the institution’s website. For the first time, researchers have managed to prove the existence of this enigmatic form of matter, which was theorized for the first time some 50 years ago.
Excitonium is a condensate that exhibits macroscopic quantum phenomena, such as a superconductor or superfluid, or an electronic insulating crystal. It is formed by excitons, particles that form in a very rare quantum mechanical pairing: that of an escaped electron and the hole it leaves behind.To prove its existence, the team, led by Professor of Physics Peter Abbamonte, developed a proprietary technique called electron energy loss spectroscopy with impulse resolution (M-EELS, for its acronym in English). With this tool, scientists were able to measure for the first time the collective excitations of the low-energy bosonic particles-the electrons and their paired holes-independently of their momentum.
More specifically, the team achieved the first observation of the precursor of exciton condensation in any material, in a soft plasmon phase that arises when the material approaches a critical temperature of 190 degrees Kelvin. According to the scientists, this phase of soft plasmon is an “irrefutable proof” of the condensation of the exciton in a three-dimensional solid and the first definitive evidence of the existence of excitonium.
This research is very promising to solve existing mysteries in quantum mechanics. At the end of the day, the study of macroscopic quantum phenomena is what has shaped the very understanding of this branch of physics. Beyond this, scientists are studying the possible technological applications of excitonium.
The work of the researchers was published this December 8 in the journal Science.