2018/02/25 by Keiichirō Nasu, Nasu, Keiichiro
Physics and Astronomy · #Advanced Chemical Physics Studies #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Quantum, superfluid, helium dynamics
paper · pdf · doi:10.48550/arxiv.1802.08944
openalex publication_date 2018/02/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Real time quantum dynamics of the spontaneous translational symmetry breakage in the early stage of photoinduced structural phase transitions is reviewed and supplementally explained, under the guide of the Toyozawa theory, which is exactly in compliance with the conservation laws of the total momentum and energy. At the Franck Condon state, an electronic excitation just created by a visible light, is in a plane wave state, extended all over the crystal. While, after the lattice relaxation having been completed, it is localized around a certain lattice site of the crystal, as a new excitation. Is there a sudden shrinkage of the excitation wave function, in between. The wave function never shrinks, but only the spatial, or inter lattice site quantum coherence, interference of the excitation disappears, as the lattice relaxation proceeds. This is nothing but the spontaneous breakage of translational symmetry.