  Negative magnetoresistance is one of the manifestations of the chiral anomaly
in Weyl semimetals. The magneto-optical conductivity also shows transitions
between Landau levels that are not spaced as in an ordinary electron gas. How
are such topological properties modified by interactions and temperature? We
answer this question by studying a lattice model of Weyl semimetals with an
on-site Hubbard interaction. Such an interacting Weyl semimetal, dubbed as Weyl
liquid, may be realized in Mn$_3$Sn. We solve that model with single-site
dynamical mean-field theory. We find that in a Weyl liquid, quasiparticles can
be characterized by a quasiparticle spectral weight $Z$, although their
lifetime increases much more rapidly as frequency approaches zero than in an
ordinary Fermi liquid. The negative magnetoresistance still exists, even though
the slope of the linear dependence of the DC conductivity with respect to the
magnetic filed is decreased by the interaction. At elevated temperatures, a
Weyl liquid crossesover to bad metallic behavior where the Drude peak becomes
flat and featureless.
