'Incoherent excitations' govern key phase of superconductor behavior

'Incoherent excitations' govern key phase of superconductor behavior: A central debate in the field has focused on whether high-temperature superconductivity--the ability to conduct electricity without resistance at record high temperatures--emerges from a fluid of individual Fermi liquid quasiparticles (the electron-like entities 'dressed' by the interactions with their surrounding that give rise to conventional low-temperature superconductivity), or is instead a property connected to the physics of 'strongly-correlated' Mott insulators, in which many-body electron behavior wipes quasiparticles completely out of existence.
Damascelli's team was able to measure a rapid loss of quasiparticle integrity in the material's electron behavior upon entering the cuprates' underdoped phase. "This implies that some very important concepts of Fermi liquid models breakdown entering this phase, and that we'll have to look in other theoretical directions to explain superconductivity."