The Bethe-Salpeter equation plays a crucial role in understanding the physics of correlated fermions, relating to optical excitations solids as well resonances high-energy physics. Yet, it is notoriously difficult control numerically, typically requiring an effort that scales polynomially with energy and accuracy. This puts many interesting systems out computational reach. Using intermediate re...

We investigate coherent matter wave transport in isotropic 3D speckle potentials by using the Bethe–Salpeter equation and self-consistent theory of localization. This model constitutes an efficient tool to properly evaluate corrections Boltzmann diffusion taking into consideration quantum interference terms between multiple-scattering paths. calculate analytically numerically static current den...

We study a method for solving the homogeneous Bethe-Salpeter equation. By introducing a ‘fictitious’ eigenvalue λ the homogeneous BetheSalpeter equation is interpreted as a linear eigenvalue equation, where the bound state mass is treated as an input parameter. Using the improved ladder approximation with the constant fermion mass, we extensively study the spectrum of the fictitious eigenvalue ...

A popular three-dimensional reduction of the Bethe–Salpeter formalism for the description of bound states in quantum field theory is the Salpeter equation, derived by assuming both instantaneous interactions and free propagation of all bound-state constituents. Numerical (variational) studies of the Salpeter equation with confining interaction, however, observed specific instabilities of the so...

The bound state Bethe-Salpeter amplitude was expressed by Nakanishi using a two-dimensional integral representation, in terms of a smooth weight function g, which carries the detailed dynamical information. A similar, but one-dimensional, integral representation can be obtained for the Light-Front wave function in terms of the same weight function g. By using the generalized Stieltjes transform...

The aim of this four-day workshop is to assess the present status, the latest achievements and future perspectives of first principles approaches to the study of spectroscopic properties of solids, nanostructures, systems with increasing complexity, and materials of technological and biological interest. More specifically, this workshop will offer the opportunity to take a look back on ten year...