Noise and Correlation Study of Quantum Hall Devices

We report voltage noise measurements on the cryogenic quantum Hall resistance (QHR) and present two new findings to illustrate the potential of the two-channel instrumentation used. Without applied current, only Johnson-Nyquist noise is present, but at two separate pairs of quantum Hall terminals, it can be cross-correlated via a longitudinal resistance. With applied current, excess noise due to dissipation bursts appears, which increases dramatically with the noninteger fraction of the filling factor.