  "Magnetic monopole" is an exotic quantum excitation in pyrochlore U(1) spin
liquid, and its emergence is purely of quantum origin and has no classical
analogue. We predict topological thermal Hall effect (TTHE) of "magnetic
monopoles" and present this prediction through non-Kramers doublets. We observe
that, when the external magnetic field polarizes the Ising component of the
local moment, internally this corresponds to the induction of emergent dual
U(1) gauge flux for the "magnetic monopoles". The motion of "magnetic
monopoles" is then twisted by the induced dual gauge flux. This emergent
Lorentz force on "magnetic monopoles" is the fundamental origin of TTHE.
Therefore, TTHE would be a direct evidence of the "monopole"-gauge coupling and
the emergent U(1) gauge structure in pyrochlore U(1) spin liquid. Our result
does not depend strongly on our choice of non-Kramers doublets for our
presentation, and can be well extended to Kramers doublets. Our prediction can
be readily tested among the pyrochlore spin liquid candidate materials. We give
a detailed discussion about the expectation for different pyrochlore magnets.
