Speaker: Lara Faoro, Laboratoire de Physique Theorique et Hautes Energies
Abstract: I review the main sources of noise in superconducting circuits: charge noise, critical current noise, quasiparticle poisoning and flux noise. I discuss the microscopic mechanism for these noises and show that charge and critical current noise are accounted for by the microscopic model that assumes the presence of localized electron states at the Superconductor Insulator interfaces. Due to the large electron electron interaction these states form resonances close to the Fermi surface. These states serve as traps where the quasiparticles live for a long time. The spins of the quasiparticles in these states produce flux noise of the right magnitude and frequency dependence. However the correlation between the magnetization and susceptibility noise observed by R. McDermott remains unexplained.