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There are opportunities for the application of chemical physics style thinking to models central to solid state physics. Solid state physics has largely been left to its own devices by the chemical physics theory community, which is a shame. I will show here that cross fertilization of ideas is real and beneficial to science. This essay is written with the hope of encouraging young theorists with a chemical physics background to enter this rich and promising area. There are many low hanging fruit available essentially because condensed matter physics traditions, models, and standards for progress are so much different than in chemical physics. By way of a warning label, right now neither community is supporting this endeavor. I am hoping this article will help, a little. I make the apology for using mainly (but not exclusively) my own narrow experience and contributions to illustrate this essay. I understand it is only a small piece of the pie, but I do believe the message here is larger: a chemical physics mindset is complementary to the condensed matter physics mindset, and they would work best together.

 

Within a tight-binding approximation, we numerically determine the time evolution of graphene electronic states in the presence of classically vibrating nuclei. There is no reliance on the Born–Oppenheimer approximation within the p-orbital tight-binding basis, although our approximation is “atomically adiabatic”: the basis p-orbitals are taken to follow nuclear positions. Our calculations show that the strict adiabatic Born–Oppenheimer approximation fails badly. We find that a diabatic (lazy electrons responding weakly to nuclear distortions) Born–Oppenheimer model provides a much more accurate picture and suggests a generalized many-body Bloch orbital-nuclear basis set for describing electron–phonon interactions in graphene. 

This study analyzed the scar-like localization in the time-average of a time-evolving wavepacket on a desymmetrized stadium billiard. When a wavepacket is launched along the orbits, it emerges on classical unstable periodic orbits as a scar in stationary states. This localization along the periodic orbit is clarified through the semiclassical approximation. It essentially originates from the same mechanism of a scar in stationary states: piling up of the contribution from the classical actions of multiply repeated passes on a primitive periodic orbit. To achieve this, several states are required in the energy range determined by the initial wavepacket.