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A stochastic approach to time-dependent density functional theory (TDDFT) is developed for computing the absorption cross section and the random phase approximation (RPA) correlation energy. The core idea of the approach involves…

Chemical Physics · Physics 2016-11-04 Yi Gao , Daniel Neuhauser , Roi Baer , Eran Rabani

We develop methods to learn the correlation potential for a time-dependent Kohn-Sham (TDKS) system in one spatial dimension. We start from a low-dimensional two-electron system for which we can numerically solve the time-dependent…

Machine Learning · Statistics 2022-12-08 Harish S. Bhat , Kevin Collins , Prachi Gupta , Christine M. Isborn

Time-Dependent Density Functional Theory (TDDFT) has recently been extended to describe many-body open quantum systems (OQS) evolving under non-unitary dynamics according to a quantum master equation. In the master equation approach,…

Chemical Physics · Physics 2015-05-18 David G. Tempel , Mark A. Watson , Roberto Olivares-Amaya , Alán Aspuru-Guzik

In this comparative study we benchmark a recently developed non-adiabatic exchange-correlation potential within time-dependent density functional theory (TDDFT) (Phys.\ Rev.\ Lett.\ {\bf 120}, 157701 (2018)) by (a) validating the transient…

Statistical Mechanics · Physics 2019-02-20 Niklas Dittmann , Nicole Helbig , Dante M. Kennes

We present the extension of Frozen Density Embedding (FDE) theory to real-time Time Dependent Density Functional Theory (rt-TDDFT). FDE a is DFT-in-DFT embedding method that allows to partition a larger Kohn-Sham system into a set of…

Chemical Physics · Physics 2015-06-23 Alisa Krishtal , Davide Ceresoli , Michele Pavanello

Time-dependent density-functional theory (TDDFT) is a formally exact approach to the time-dependent electronic many-body problem which is widely used for calculating excitation energies. We present a survey of the fundamental framework,…

Materials Science · Physics 2014-01-29 Carsten A. Ullrich , Zeng-hui Yang

Time-dependent density-functional theory (TDDFT) treats dynamical exchange and correlation (xc) via a single-particle potential, Vxc(r,t), defined as a nonlocal functional of the density n(r',t'). The popular adiabatic local-density…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. A. Ullrich , I. V. Tokatly

We present an application of our new theoretical formulation of quantum dynamics, moment propagation theory (MPT) (Boyer et al., J. Chem. Phys. 160, 064113 (2024)), for employing machine-learning techniques to simulate the quantum dynamics…

Chemical Physics · Physics 2024-12-09 Nicholas J. Boyer , Christopher Shepard , Ruiyi Zhou , Jianhang Xu , Yosuke Kanai

Long-range charge transfer excited states are notoriously badly underestimated in time-dependent density functional theory (TDDFT). We resolve how {\it exact} TDDFT captures charge transfer between open-shell species: in particular the role…

Chemical Physics · Physics 2009-11-11 Neepa T. Maitra

Density functional theory (DFT) and linear-response time-dependent density functional theory (LR-TDDFT) rely on an exchange-correlation (xc) approximation that provides not only energy but also its functional derivatives that enter the…

Chemical Physics · Physics 2026-04-08 Xiaoyu Zhang

In principle, we should not need the time-dependent extension of density-functional theory (TDDFT) for excitations, and in particular not for Molecular Dynamics (MD) studies: the theorem by Hohenberg and Kohn teaches us that for any…

Strongly Correlated Electrons · Physics 2015-05-27 J. L. Alonso , Alberto Castro , Pablo Echenique , Angel Rubio

In this work we have studied a new functional for the correlation energy obtained from the exact-exchange (EXX) approximation within time-dependent density functional theory (TDDFT). Correlation energies have been calculated for a number of…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Maria Hellgren , Ulf von Barth

We present a new class of non-adiabatic approximations in time-dependent density functional theory derived from an exact expression for the time-dependent exchange-correlation potential. The approximations reproduce dynamical step and peak…

Chemical Physics · Physics 2018-12-21 Lionel Lacombe , Neepa T. Maitra

In their famous paper Kohn and Sham formulated a formally exact density-functional theory (DFT) for the ground-state energy and density of a system of $N$ interacting electrons, albeit limited at the time by certain troubling…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 Miquel Huix-Rotllant , Mark E. Casida

The time-dependent exchange-correlation potential has an unusual task in directing fictitious non-interacting electrons to move with exactly the same probability density as true interacting electrons. This has intriguing implications for…

Chemical Physics · Physics 2024-06-19 Davood Dar , Lionel Lacombe , Neepa T. Maitra

Time-dependent density-functional theory (TDDFT) is a computationally efficient first-principles approach for calculating optical spectra in insulators and semiconductors, including excitonic effects. We show how exciton wave functions can…

Materials Science · Physics 2020-12-29 Jared R. Williams , Nicolas Tancogne-Dejean , Carsten A. Ullrich

Time-dependent density functional theory (TDDFT) is presently enjoying enormous popularity in quantum chemistry, as a useful tool for extracting electronic excited state energies. This article explains what TDDFT is, and how it differs from…

Materials Science · Physics 2007-05-23 Peter Elliott , Kieron Burke , Filipp Furche

Time-dependent density functional theory continues to draw a large number of users in a wide range of fields exploring myriad applications involving electronic spectra and dynamics. Although in principle exact, the predictivity of the…

Chemical Physics · Physics 2023-08-14 Lionel Lacombe , Neepa T. Maitra

We illustrate the scope of Time Dependent Density Functional Theory (TDDFT) for strongly correlated (lattice) models out of equilibrium. Using the exact many body time evolution, we reverse engineer the exact exchange correlation (xc)…

Mesoscale and Nanoscale Physics · Physics 2008-08-12 Claudio Verdozzi

Recent progress has been made in capturing spectral features of electronic states of double-excitation character in time-dependent density functional theory (TDDFT) through a frequency-dependent kernel. While it might appear that this…

Chemical Physics · Physics 2026-05-04 Dhyey Ray , Anna Baranova , Davood B. Dar , Neepa T. Maitra