Effect of Nyquist noise on the Nyquist dephasing rate in two-dimensional electron systems

We measure the effect of externally applied broadband (100 MHz-10 GHz) Nyquist noise on the intrinsic Nyquist dephasing rate of electrons in a two-dimensional electron gas at low temperatures. Within the measurement error, the phase coherence time is unaffected by the externally applied Nyquist noise, including applied noise temperatures of up to 300 K. The amplitude of the applied Nyquist noise is quantitatively determined in the same experiment using a microwave network analyzer.