Theoretical studies of strongly correlated electronic systems

David Sénéchal, A.–M. S. Tremblay, C. Bourbonnais

M. Schaefer

Strongly correlated electron systems (SCES) represent a class of quantum materials where electron-electron interactions play a dominant role in determining physical properties, leading to a wide array of exotic phenomena such as high-temperature superconductivity, quantum spin liquids, Mott transitions, and heavy fermion behavior. Unlike weakly interacting systems described adequately by Fermi-liquid theory, SCES require more advanced theoretical frameworks due to the breakdown of single-particle descriptions. This article reviews the fundamental interactions governing SCES, emphasizing Coulomb repulsion, spin-charge separation, and entanglement-driven effects. The role of lattice geometry, orbital degeneracy, and dimensionality is explored to understand emergent behaviors. Through theoretical insights and recent experimental findings, this work outlines how these fundamental interactions shape the rich phase diagrams of SCES and their implications in quantum technologies.

Daniel Q. Duffy

Ryōen Shirasaki, Kaoru Iwano

One-dimensional strongly correlated electron system, which is accompanied by interaction with the lattice, has attracted a great deal of interest in both experimental and theoretical studies. At half-filling, this system is a Mott insulator when the electron–lattice interaction is weak. We performed a theoretical investigation of the stable ground state of the one-dimensional strongly correlated electron system with electron–lattice interaction in which one electron is doped from half-filling. We used an extended Peierls–Hubbard model. We report here that, contrary to “common sense” suppositions about the one-dimensional electron–lattice system, a polaron solution appears under conditions of comparatively strong electron–lattice interaction in the Mott phase and that the polaron delocalizes under conditions of weak electron–lattice interaction. These two states are separated by the strength of the electron–lattice interaction.

Philip A. E. Murgatroyd