Dresden 2026 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 15: Phase Transformations I

MM 15.1: Talk

Tuesday, March 10, 2026, 14:00–14:15, SCH/A215

Quantum Geometric Injection and Shift Optical Forces Drive Coherent Phonons — •Luke Pimlott and Habib Rostami — University of Bath, Bath, United Kingdom

We identify injection and shift rectified Raman forces, which are phononic counterparts of the photogalvanic effect, that drive lattice vibrations and trigger transient emergent properties. These forces are governed by the quantum geometric tensor, a phononic shift vector, and interband asymmetries in the electron-phonon coupling. As a response to pulsed light, the injection force induces displacive atomic motion, while, unlike conventional impulsive mechanisms, the shift force produces impulsive atomic displacement in the resonant interband absorbing regime when time-reversal symmetry is broken. Using the bilayer Haldane model, we quantify the injection and shift forces acting on interlayer shear phonons through both analytical and numerical methods. Strikingly, we reveal strong tunability, both in magnitude and direction, of the rectified forces by varying the driving frequency and magnetic flux, uncovering a distinct quantum geometric mechanism for ultrafast and coherent manipulation of quantum materials.

Keywords: Nonlinear optics; Phonons; Layered materials; Quantum geometry; Electron-phonon coupling