D. Bustamante: Phonon-Driven Control of Polarization, Magnetism, and Transport in Quantum Materials

Coherent lattice vibrations provide a powerful way to steer quantum materials out of equilibrium on ultrafast timescales, creating transient states and responses before relaxation restores thermal order. This dissertation develops and applies a unified physical picture in which infrared-active phonons are not passive lattice excitations, but active dynamical degrees of freedom that can manipulate electric, magnetic, and transport behavior through symmetry-selective couplings. The central idea is that driven phonons can reshape effective energy landscapes and generate nonlinear re- sponses that appear as rectified order, frequency conversion, controlled dynamics, and transport phenomena.