  The unambiguous identification of Majorana zero modes (MZMs) is one of the
most outstanding problems of condensed matter physics. Thermal transport
provides a detection tool that is sensitive to these chargeless quasiparticles.
We study thermoelectric transport between metallic leads transverse to a
Josephson junction. The central double quantum dot hosts conventional or
topological Andreev states that depend on the phase difference $\phi$. We show
that the presence of MZMs can be identified by a significant amplification of
both the electrical and thermal conductance at $\phi \approx \pi$ as well as
the Seebeck coefficient at $\phi \approx 0$. We further investigate the
robustness of our results against Cooper pair splitting processes.
