Quantum origins of the chiral vortical effect, beyond semi-classical.

The chiral vortical effect (CVE) refers to generation of an axial current J in a rotating ω Weyl fermion and is relevant to broad contexts ranging from parity violating interactions involving neutrinos to transport in Weyl semimetals. It is invariably described using semiclassical approaches, leaving its underlying quantum origins mysterious. In this work, we develop a fully quantum description of the CVE. Besides reproducing established semiclassical results, we uncover new features for CVE in Weyl fermions: (1) linearity J ~ ω could be strict, i.e., quantum model (possibly with anisotropy) suggests vanishing higher orders J ~ ωⁿ; (2) the essential role of non-equilibrium in enabling the effect, setting CVE distinguished from the chiral magnetic effect (CME). The non-equilibrium causes characteristic modifications to Maxwell’s equations that carry fingerprints of the chiral anomaly.