Physicists solve a quantum mystery that stumped scientists for decades

Physicists have developed a new theory that brings together two major areas of modern quantum physics. The work explains how a single unusual particle behaves inside a crowded quantum environment known as a many-body system. In this setting, the particle can act either as something that moves freely or as something that remains nearly fixed within a vast collection of fermions, often called a Fermi sea. Researchers at the Institute for Theoretical Physics at Heidelberg University c...