Isosbestic points in the spectral function of correlated electrons

TL;DR

This paper studies the spectral function of correlated electrons in the Hubbard model, revealing isosbestic points that intersect at specific energies, offering insights into the microscopic energy scales of such systems.

Contribution

It identifies and analyzes isosbestic points in the spectral function of correlated electrons, linking their locations to the non-interacting band structure.

Findings

Isosbestic points occur near the band edges of the non-interacting system.

The location of these points depends on the details of the band structure.

These points provide insights into the energy scales of correlated systems.

Abstract

We investigate the properties of the spectral function A(omega,U) of correlated electrons within the Hubbard model and dynamical mean-field theory. Curves of A(omega,U) vs. omega for different values of the interaction U are found to intersect near the band-edges of the non-interacting system. For a wide range of U the crossing points are located within a sharply confined region. The precise location of these 'isosbestic points' depends on details of the non-interacting band structure. Isosbestic points of dynamic quantities therefore provide valuable insights into microscopic energy scales of correlated systems.