Bulk Topological Plasmons in Doped Weyl Metals

Weyl metals host massless chiral fermions carrying monopole charges in momentum space. We develop a microscopic theory of collective charge oscillations — bulk topological plasmons — in a single-valley doped Weyl metal within the random-phase and Bethe-Salpeter frameworks. Analytical evaluation of the polarization function reveals logarithmic corrections to the relativistic plasmon frequency and the absence of plasmons at charge neutrality. We show that plasmon eigenstates exhibit Berry curvature and quantized monopole charge in both the center-of-mass and relative-motion spaces, originating from inter-band electron-hole correlations. Moreover, we propose that the topology of the relative-motion space can be experimentally probed through plasmon optical selection rules, establishing a direct correspondence between the quantum geometry of collective modes and the topological structure of Weyl nodes.