  Using newly developed quantum-classical hybrid framework, we investigate
interaction between spin-polarized conduction electrons and a single spin wave
(SW) coherently excited within a metallic ferromagnetic nanowire. When the
nanowire hosting SW is attached to two normal metal (NM) leads, with no dc bias
voltage applied between them, the SW pumps chiral electronic charge and spin
currents into the leads---their direction is tied to the direction of SW
propagation and they scale linearly with the frequency of the precession. This
is in contrast to: standard pumping by the uniform precession mode with
identical spin currents flowing in both directions and no accompanying charge
current; or experimentally observed [C.~Ciccarelli et al., Nat. Nanotech. 10,
50 (2014); M.~Evelt et al., Phys. Rev. B 95, 024408 (2017)] magnonic charge
pumping which requires spin-orbit coupling spin-orbit coupling. The mechanism
behind our prediction is nonadiabaticity due to time-retardation
effects---motion of localized magnetic moment affects conduction electron spin
in a retarded way, so that it takes a finite time until the electron spin
reacts to the motion of the classical vector. Upon injecting dc spin-polarized
charge current from the left NM lead, electrons interact with SW where
outflowing charge and spin current into the right NM lead are changed due to
both scattering off time-dependent potential generated by the SW and
superposition with the currents pumped by the SW itself. Using Lorentzian
voltage pulse to excite leviton out of the Fermi sea, which carries one
electron charge with no accompanying electron-hole pairs and behaves as
soliton-like quasiparticle, we describe how a single electron interacts with a
single SW.
