Quantized phase-coherent heat transport of counterpropagating Majorana modes

Propagating Majorana modes at the edge of topological superconductors are promising candidates for future qubits in fault-tolerant quantum computing. However, their experimental detection by electrical means is challenging. In this work, the authors propose the phase-dependent transverse thermal conductance of Josephson junctions as a new way to probe helical Majorana modes. They give rise to a thermal conductance that is quantized by half the thermal conductance quantum, while trivial Andreev bound states lead to an exponentially suppressed thermal conductance.