  Heat transport in multiple quantum-Hall edge channels at Landau-level filling
factor nu = 2, 4, and 8 is investigated with a quantum point contact as a heat
generator and a quantum dot as a local thermometer. Heat distribution among the
channels remains highly non-uniform, which can be understood with the plasmon
eigenmodes of the multiple channels. The heat transport can be controlled with
another quantum point contact as a quantized heat valve, as manifested by
stepwise increases of heat current at the thermometer. This encourages
developing integrated heat circuits with quantum-Hall edge channels.
