Fig. 5: Ultrafast manipulation of finite-momentum spin waves.
From: Probing light-driven quantum materials with ultrafast resonant inelastic X-ray scattering
a Ultrafast pulses can be used to directly manipulate magnetic excitations in quantum materials through a direct modulation of the effective exchange interactions Jeff. b A possible mechanism consists of dressing the intermediate doubly occupied state with the pump field, which is lifted (lowered) in energy by an amount proportional to the number of virtually absorbed (emitted) pump photons. U is the onsite Coulomb repulsion, teff the effective hopping amplitude, Ω the pump photon energy and m the Floquet index. c As the exchange interactions are modulated, the spin wave dispersion is expected to shift in energy (ω) across the entire Brillouin zone. A cross-section cut (gray shaded planes) along two high-symmetry directions is included for clarity.
