Dependency of quantum time scales on symmetry
Abstract
Although used extensively in everyday life, time is one of the least understood quantities in physics, especially on the level of quantum mechanics. Here we use an experimental method based on spin- and angle-resolved photoemission spectroscopy from spin-degenerate dispersive states to determine the Eisenbud-Wigner-Smith (EWS) time delay of photoemission. This time scale of the quantum transition is measured for materials with different dimensionality and correlation strength. A direct link between the dimensionality, or rather the symmetry of the system, and the attosecond photoionisation time scale is found. The quasi 2-dimensional transition metal dichalcogenides 1T-TiSe and 1T-TiTe show time scales around 150 as, whereas in quasi 1-dimensional CuTe the photoionisation takes more than 200 as. This is in stark contrast with the 26 as found for 3-dimensional pure Cu. These results provide new insights into the role of symmetry in quantum time scales and may provide a route to understanding the role of time in quantum mechanics.
Keywords
Cite
@article{arxiv.2506.01476,
title = {Dependency of quantum time scales on symmetry},
author = {Fei Guo and Dmitrii Usanov and Eduardo B. Guedes and Mauro Fanciulli and Kaishu Kawaguchi and Ryo Mori and Takeshi Kondo and Arnaud Magrez and Michele Puppin and Hugo Dil},
journal= {arXiv preprint arXiv:2506.01476},
year = {2026}
}