Electron quadrupling condensates

For more than a century, one of the central topics in physics was superconductivity, discovered in 1911. This phenomenon is caused by the formation and condensation of pairs of electrons. Could there be condensates involving the formation of electron quadruplets? Such states are impossible within the paradigm of the standard Bardeen-Copper-Schrieffer theory.

However, in the last two decades, different theoretical mechanisms were proposed, pointing to the tantalizing possibility that electron quadrupling condensates may exist.

Several months ago, an international experimental consortium collaborating with our theory group reported the first clear evidence of electron quadrupling condensate. This new  state of matter  was found in Ba1−xKxFe2As2 in the vicinity of x=0.8. The experiments reveal many unconventional properties that opened up  many fundamental questions.

In this project, we will use a large spectrum of theoretical methods to address the questions that include: what is the effective  model that describes that state, what are the elementary, collective and topological excitations in that state, what are the microscopic theories of the observed unusual transport, thermoelectric and magnetic properties.

Finally, we will investigate other candidate materials where other electron quadrupling condensates may form.