0000000000447105
AUTHOR
Thomas Schäfer
Momentum structure of the self-energy and its parametrization for the two-dimensional Hubbard model
We compute the self-energy for the half-filled Hubbard model on a square lattice using lattice quantum Monte Carlo simulations and the dynamical vertex approximation. The self-energy is strongly momentum dependent, but it can be parametrized via the non-interacting energy-momentum dispersion $\varepsilon_{\mathbf{k}}$, except for pseudogap features right at the Fermi edge. That is, it can be written as $\Sigma(\varepsilon_{\mathbf{k}},\omega)$, with two energy-like parameters ($\varepsilon$, $\omega$) instead of three ($k_x$, $k_y$ and $\omega$). The self-energy has two rather broad and weakly dispersing high energy features and a sharp $\omega= \varepsilon_{\mathbf{k}}$ feature at high tem…
Fate of the false Mott-Hubbard transition in two dimensions
We have studied the impact of non-local electronic correlations at all length scales on the Mott-Hubbard metal-insulator transition in the unfrustrated two-dimensional Hubbard model. Combining dynamical vertex approximation, lattice quantum Monte-Carlo and variational cluster approximation, we demonstrate that scattering at long-range fluctuations, i.e., Slater-like paramagnons, opens a spectral gap at weak-to-intermediate coupling -- irrespectively of the preformation of localized or short-ranged magnetic moments. This is the reason, why the two-dimensional Hubbard model is insulating at low enough temperatures for any (finite) interaction and no Mott-Hubbard transition is observed.
What makes us like music?
Why do we like the music we like and why do different people like different kinds of music? Existing models try to explain music preference as an interplay of musical features, the characteristics of the listener, and the listening context. Hereby, they refer to short-term preference decisions for a given piece of music rather than to the question why we listen to music at all and why we select a particular musical style. In this paper, it is hypothesized that the motivation for music listening and the liking for a particular kind of music depend on the functions that this music can fulfill for the listener. Thus, the relative contribution of these functions to the development of music pref…