Anomalous Magnetothermal Resistance of High-Tc Superconductors: Anomalous Cyclotron Orbits at a Dirac Point

I derive equations of motion for quasiparticles near the nodes in the d-wave gap of high Tc superconductors. Previous versions have not properly taken into account the spatial dependence of the gap parameter phase. The results are compatible with magnetothermal conductivity measurements in the superconducting phase by Ong and Krishana.