536 citations · 1.2k across the 13 of their papers we have counts for
13 papers
Approximations based on density-matrix embedding theory for density-functional theories
Iris Theophilou, Teresa E. Reinhard, Angel Rubio +1
Recently a novel approach to find approximate exchange-correlation functionals in density-functional theory (DFT) was presented (U. Mordovina et. al., JCTC 15, 5209 (2019)), which…
Light-matter hybrid-orbital-based first-principles methods: the influence of the polariton statistics
Florian Buchholz, Iris Theophilou, Klaas J. H. Giesbertz +2
A detailed understanding of strong matter-photon interactions requires first-principle methods that can solve the fundamental Pauli-Fierz Hamiltonian of non-relativistic quantum el…
Virial relations for electrons coupled to quantum field modes
Iris Theophilou, Markus Penz, Michael Ruggenthaler +1
In this work we present a set of virial relations for many electron systems coupled to field modes, described by the Pauli--Fierz Hamiltonian in dipole approximation and using leng…
Octopus, a computational framework for exploring light-driven phenomena and quantum dynamics in extended and finite systems
Nicolas Tancogne-Dejean, Micael J. T. Oliveira, Xavier Andrade +31
Over the last years extraordinary advances in experimental and theoretical tools have allowed us to monitor and control matter at short time and atomic scales with a high-degree of…
Force Balance Approach for Advanced Approximations in Density Functional Theories
Mary-Leena M. Tchenkoue, Markus Penz, Iris Theophilou +2
We propose a systematic and constructive way to determine the exchange-correlation potentials of density-functional theories including vector potentials. The approach does not rely…
Reduced Density-Matrix Approach to Strong Matter-Photon Interaction
Florian Buchholz, Iris Theophilou, Soeren Ersbak Bang Nielsen +2
We present a first-principles approach to electronic many-body systems strongly coupled to cavity modes in terms of matter-photon one-body reduced density matrices. The theory is f…
Kinetic-Energy Density-Functional Theory on a Lattice
Iris Theophilou, Florian Buchholz, F. G. Eich +2
We present a kinetic-energy density-functional theory and the corresponding kinetic-energy Kohn-Sham (keKS) scheme on a lattice and show that by including more observables explicit…
Structure of the first order Reduced Density Matrix in three electron systems: A Generalized Pauli Constraints assisted study
Iris Theophilou, Nektarios Lathiotakis, Nicole Helbig
We investigate the structure of the one-body Reduced Density Matrix (1RDM) of three electron systems, i.e. doublet and quadruplet spin configurations, corresponding to the smallest…
Conditions for describing triplet states in reduced density matrix functional theory
Iris Theophilou, Nektarios N. Lathiotakis, Nicole Helbig
We consider necessary conditions for the one-body-reduced density matrix (1RDM) to correspond to a triplet wave-function of a two electron system. The conditions concern the occupa…
Orbitals from local RDMFT: Are they Kohn-Sham or Natural Orbitals?
Iris Theophilou, Nektarios N. Lathiotakis, Nikitas I. Gidopoulos +2
Recently, an approximate theoretical framework was introduced, called local reduced density matrix functional theory (local-RDMFT), where functionals of the one-body reduced densit…
Generalized Pauli constraints in reduced density matrix functional theory
Iris Theophilou, Nektarios N. Lathiotakis, Miguel A. L. Marques +1
Functionals of the one-body reduced density matrix (1-RDM) are routinely minimized under Coleman's ensemble -representability conditions. Recently, the topic of pure-state -r…
Real-space grids and the Octopus code as tools for the development of new simulation approaches for electronic systems
Xavier Andrade, David A. Strubbe, Umberto De Giovannini +13
Real-space grids are a powerful alternative for the simulation of electronic systems. One of the main advantages of the approach is the flexibility and simplicity of working direct…
Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme
Iris Theophilou, M. Tassi, S. Thanos
Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and compu…