Heat current fluctuations in quantum wires

Noise in the thermal current through a ballistic quantum wire is considered both for noninteracting and interacting particles. It is shown that for a perfect quantum wire the equilibrium thermal (Johnson-Nyquist) noise does not depend on the statistics of the heat carriers. In contrast, the nonequilibrium noise, produced by the temperature difference between the heat baths, is different for fermions and bosons. The general expressions which are obtained, are used in calculations of the noise power of the thermal current through a Luttinger liquid wire connected to reservoirs of noninteracting electrons.