A Fully Linear Response G₀W₀ Method That Scales Linearly up to Tens of Thousands of Cores

Abstract

We present a G 0 W 0 approach that is based on the evaluation of the linear response of the actions of the G 0 and W 0 operators. In this way we avoid sums over empty one-particle orbitals and do not have to explicitly develop the screened Coulomb interaction W 0 on a dedicated basis. For a given orbital, the self-energy is found by summing terms relative to a set of points in the real-space simulation cell. This permits us to easily control the ratio of the accuracy to the computational cost. A trivial parallelization strategy allows strong linear scaling up to tens of thousands of computing cores.

Spatial Decay and Limits of Quantum Solute–Solvent Interactions

“…Many-body Green’s function methods , provide direct access to single-quasiparticle energies, provided that the system is weakly or moderately correlated. Indeed, the GW approximation, − even at the lowest-order expansion in which the electronic correlation is described merely through charge density fluctuations, yields IPs that agree with experiments for most molecular systems. − Recent developments in efficient algorithms − and high-performance computing, − especially the linear-scaling stochastic formalism, − have enabled large-scale GW calculations for systems with thousands of electrons. Within the stochastic GW framework, ,, our previous work established an efficient approach for computing the photoemission spectra (i.e., IPs) of various solvated molecules, in which the solute and the solvent environment (containing ∼1000 electrons) are treated on the same footing.…”

Koopmans Spectral Functionals in Periodic Boundary Conditions

“…Nevertheless, these high-level methods are often limited in system size and complexity, due to their computational cost and numerical complexity. Despite many efforts dedicated to improving efficiency of Green’s function methods, − simpler methods based on KS-DFT, possibly including some fraction of nonlocal exchange, are still frequently employed to approximately evaluate the spectral properties of nanostructures, interfaces, and solids. In this respect, Koopmans-compliant (KC) functionals − have been introduced to bridge the gap between KS-DFT and Green’s function theory. , KC functionals retain the advantages of a functional formulation by enforcing physically motivated conditions to approximate density functionals.…”