Universal conductance fluctuations imply excess high frequency noise in mesoscopic gold wires.

In cold, mesoscopic conductors, two-level fluctuators lead to time-dependent conductance fluctuations manifested as 1/f noise that are enhanced by quantum interference up to a universal limit (TDUCF). In Au nanowires, we measure the magnetic field dependence of TDUCF, weak localization (WL), and magnetic field-driven (MF) UCF before and after treatments that alter magnetic scattering and passivate surface fluctuators. Our coherence length data resolve a long-standing inconsistency between L$_{WL}$ and L$_{TDUCF}$, and may imply that fluctuators produce high frequency noise in excess of 1/f expectations.