Electrons in-between

Guido Burmeister, Klaus Maschke

We consider N electrons in a one-dimensional loop enclosing a static magnetic flux. The electronic positions are described in terms of collective and relative coordinates. The corresponding partition of the Hilbert space is particularly convenient to investigate the electronic spectrum in the range of large electron-electron interaction. The electronic current is determined by the collective motion of the electrons. Thus, in absence of backscattering by a one-particle potential, the electron-electron interaction does not affect the persistent current associated with the electronic ground state. This is different when backscattering is present, since then collective and relative motions are coupled. We present a detailed study of the interplay between potential backscattering and electron-electron interaction, which is revealed by the resulting ground-state currents as well as by the electronic excitation spectra.

Thomas P. Pearsall

G-Q Hai, L Cândido, B G A Brito +1 more

Starting from the shell structure in atoms and the significant correlation within electron pairs, we distinguish the exchange-correlation effects between two electrons of opposite spins occupying the same orbital from the average correlation among many electrons in a crystal. In the periodic potential of the crystal with lattice constant larger than the effective Bohr radius of the valence electrons, these correlated electron pairs can form a metastable energy band above the corresponding single-electron band separated by an energy gap. In order to determine if these metastable electron pairs can be stabilized, we calculate the many-electron exchange-correlation renormalization and the polaron correction to the two-band system with single electrons and electron pairs. We find that the electron-phonon interaction is essential to counterbalance the Coulomb repulsion and to stabilize the electron pairs. The interplay of the electron-electron and electron-phonon interactions, manifested in the exchange-correlation energies, polaron effects, and screening, is responsible for the formation of electron pairs (bipolarons) that are located on the Fermi surface of the single-electron band.

Thomas P. Pearsall

Thomas P. Pearsall

Bing Gu, Ignacio Franco

The relationship between electronic interactions and electronic decoherence is a fundamental problem in chemistry. Here we show that varying the electron-electron interactions does not affect the electronic decoherence in the pure-dephasing limit. In this limit, the effect of varying the electronic interactions is to rigidly shift in energy the diabatic potential energy surfaces without changing their shape, thus keeping the nuclear dynamics in these surfaces that leads to the electronic decoherence intact. This analysis offers a simple and intuitive understanding of previous theoretical and computational efforts to characterize the influence of electronic interactions on the decoherence and opens opportunities to study exact electronic decoherence with approximate electronic structure theories.