  Weyl semimetals (WSMs) host charged Weyl fermions as emergent quasiparticles.
We develop a unified analytical theory for the anomalous positive longitudinal
magnetoconductance (LMC) in a WSM, which bridges the gap between the classical
and ultra-quantum approaches. More interestingly, the LMC is found to exhibit
periodic-in-$1/B$ quantum oscillations, originating from the oscillations of
the nonequilibrium chiral chemical potential. The quantum oscillations,
superposed on the positive LMC, are a remarkable fingerprint of a WSM phase
with chiral anomaly, whose observation is a valid criteria for identifying a
WSM material. In fact, such quantum oscillations were already observed by
several experiments.
