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Electronic excited states in deep variational Monte Carlo

Obtaining accurate ground and low-lying excited states of electronic systems is crucial in a multitude of important applications. One ab initio method for solving the Schrödinger equation that scales favorably for large systems is variational quantum …

Accurate total energies from the adiabatic-connection fluctuation-dissipation theorem

In the context of inhomogeneous one-dimensional finite systems, recent numerical advances [Phys. Rev. B 103, 125155 (2021)] allow us to compute the exact coupling-constant dependent exchange-correlation kernel within linear response time-dependent …

Insights from exact exchange-correlation kernels

The exact exchange-correlation (xc) kernel fxc(x,x',w) of linear response time-dependent density functional theory is computed over a wide range of frequencies for three canonical one-dimensional finite systems. Methods used to ensure the numerical …

Exact nonadiabatic part of the Kohn-Sham potential and its fluidic approximation

We present a simple geometrical “fluidic” approximation to the nonadiabatic part of the Kohn-Sham potential, vks, of time-dependent density-functional theory (DFT). This part of vks is often crucial, but most practical functionals utilize an …

Exact exchange-correlation kernels for optical spectra of model systems

For two prototype systems, we calculate the exact exchange-correlation kernels fxc(x,x',w) of time-dependent density functional theory. fxc, the key quantity for optical absorption spectra of electronic systems, is normally subject to uncontrolled …

Comparison of local density functionals based on electron gas and finite systems

A widely used approximation to the exchange-correlation functional in density functional theory is the local density approximation (LDA), typically derived from the properties of the homogeneous electron gas (HEG). We previously introduced a set of …

Local density approximations from finite systems

The local density approximation (LDA) constructed through quantum Monte Carlo calculations of the homogeneous electron gas (HEG) is the most common approximation to the exchange-correlation functional in density functional theory. We introduce an …