Physicists Have Created a New State of Matter. With Four Electrons? - Interesting Engineering

Now, KTH Professor Egor Babaev, with the aid of international collaborators, has revealed evidence of fermion quadrupling in a series of experimental measurements on the iron-based material, Ba1−xKxFe2As2.This is the first-ever experimental evidence of this quadrupling effect and the mechanism by which this state of matter occurs.Babaev's experimental collaborator at Technische Universtät Dresden, Vadim Grinenko, found in 2018 the first signs of a fermion quadrupling condensate, going against years of prevalent scientific agreement.