  We present a new scheme to detect the quantum shot noise in coupled
mesoscopic systems. By applying the noise thermometry to the capacitively
coupled quantum point contacts (QPCs) we prove that the noise temperature of
one QPC is in perfect proportion to that of the other QPC which is driven to
non-equilibrium to generate quantum shot noise. We also found an unexpected
effect that the noise in the source QPC is remarkably suppressed possibly due
to the cooling effect by the detector QPC.
