  Recent experiments demonstrate precise control over coherently excited phonon
modes using high-intensity terahertz lasers, opening new pathways towards
dynamical, ultrafast design of magnetism in functional materials. In this work,
we put forward a coupling mechanism based on electron-nuclear quantum geometry.
This effect is rooted in the phase accumulation of the electronic wavefunction
under a circular evolution of nuclear coordinates. An excitation pulse then
induces a transient level splitting between electronic orbitals that carry
angular momentum. When converted to effective magnetic fields, values on the
order of tens of Teslas are easily reached.
