Fractional charges and statistics

Sensitive shot noise measurements are performed in all quantum Hall effect states. Homemade cooled amplifiers (to temperature 1-4.2K), not too far from cold sample (at ~10mK) are used as first stage of amplification. Current fluctuations are sensitive the charge of the particles (being electrons or fractionally charges quasi-particles). The noise is also important in detecting neutral modes and measuring temperature (via the Johnson-Nyquist noise)