Beyond the random phase approximation with a local exchange vertex

Electron Liquid Beyond the Random Phase Approximation

A deeper understanding of low-dimensional and small-scale electronic systems requires an accurate characterization of the many-electron effects. Based on the electron liquid (EL) model, these many-body effects in the three-dimensional (3D) and two-dimensional (2D) electronic systems are dealt going beyond the random phase approximation within the zero-temperature framework. The dielectric formu...

Beyond the random phase approximation Improved description of short-range correlation by a renormalized adiabatic local density approximation

Beyond the random phase approximation on the cheap: Improved correlation energies with the efficient “radial exchange hole” kernel

Complexation between oppositely charged polyelectrolytes: beyond the Random Phase Approximation

We consider the phase behavior of polymeric systems by calculating the structure factors beyond the Random Phase Approximation. The effect of this correction to the mean-field RPA structure factor is shown to be important in the case of coulombic systems. Two examples are given: simple electrolytes and mixtures of incompatible oppositely charged polyelectrolytes. In this last case, all former s...

A Local 2-Approximation Algorithm for the Vertex Cover Problem

We present a distributed 2-approximation algorithm for the minimum vertex cover problem. The algorithm is deterministic, and it runs in (∆+ 1) synchronous communication rounds, where ∆ is the maximum degree of the graph. For ∆ = 3, we give a 2-approximation algorithm also for the weighted version of the problem.