In physics, the thermal conductance quantum describes the rate at which heat is transported through a single ballistic phonon channel of temperature . It is given by: . The thermal conductance of any electrically insulating structure that exhibits ballistic phonon transport is a positive integer multiple of The thermal conductance quantum was first measured in 2000. These measurements employed suspended silicon nitride nanostructures that exhibited a constant thermal conductance of 16 at temperatures below approximately 0.6 kelvin. where is a universal constant called the Lorenz factor,