  We investigate minimal excitation states for heat transport into a fractional
quantum Hall system driven out of equilibrium by means of time-periodic voltage
pulses. A quantum point contact allows for tunneling of fractional
quasi-particles between opposite edge states, thus acting as a beam splitter in
the framework of the electron quantum optics. Excitations are then studied
through heat and mixed noise generated by the random partitioning at the
barrier. It is shown that levitons, the single-particle excitations of a filled
Fermi sea recently observed in experiments, represent the cleanest states for
heat transport, since excess heat and mixed shot noise both vanish only when
Lorentzian voltage pulses carrying integer electric charge are applied to the
conductor. This happens in the integer quantum Hall regime and for Laughlin
fractional states as well, with no influence of fractional physics on the
conditions for clean energy pulses. In addition, we demonstrate the robustness
of such excitations to the overlap of Lorentzian wavepackets. Even though mixed
and heat noise have nonlinear dependence on the voltage bias, and despite the
non-integer power-law behavior arising from the fractional quantum Hall
physics, an arbitrary superposition of levitons always generates minimal
excitation states.
