Publisher's Note: Candidate Source of Flux Noise in SQUIDs: Adsorbed Oxygen Molecules [Phys. Rev. Lett. 115, 077002 (2015)].

This corrects the article DOI: 10.1103/PhysRevLett.115.077002.

Candidate Source of Flux Noise in SQUIDs: Adsorbed Oxygen Molecules.

A major obstacle to using superconducting quantum interference devices (SQUIDs) as qubits is flux noise. We propose that the heretofore mysterious spins producing flux noise could be O_{2} molecules adsorbed on the surface. Using density functional theory calculations, we find that an O_{2} molecule adsorbed on an α-alumina surface has a magnetic moment of ~1.8 µ_{B}. The spin is oriented perpendicular to the axis of the O-O bond, the barrier to spin rotations is about 10 mK. Monte Carlo simulations of ferromagnetically coupled, anisotropic XY spins on a square lattice find 1/f magnetization noise, consistent with flux noise in Al SQUIDs.

Proximity-induced superconductivity in nanowires: minigap state and differential magnetoresistance oscillations.

We study proximity-induced superconductivity in gold nanowires as a function of the length of the nanowire, magnetic field, and excitation current. Short nanowires exhibit a sharp superconducting transition, whereas long nanowires show nonzero resistance. At intermediate lengths, however, we observe two sharp transitions; the normal and superconducting regions are separated by what we call the minigap phase. Additionally, we detect periodic oscillations in the differential magnetoresistance. We suggest that the minigap phase as well as the periodic oscillations originate from a coexistence of proximity-induced superconductivity with a normal region near the center of the wire, created either by temperature or the application of a magnetic field.

Resonant tunneling in the fractional quantum Hall effect: superperiods and braiding statistics.

We study theoretically resonant tunneling of composite fermions through their quasibound states around a fractional quantum Hall island, and find a rich set of possible transitions of the island state as a function of the magnetic field or the backgate voltage. These have possible relevance to a recent experimental study, and reveal many subtleties involved in deducing fractional braiding statistics.