• Density-potential inversion from Moreau-Yosida regularization 

      Penz, Markus; Csirik, Mihaly Andras; Laestadius, Andre (Peer reviewed; Journal article, 2023)
    • Exchange energies with forces in density-functional theory 

      Tancogne-Dejean, Nicolas; Penz, Markus; Laestadius, Andre; Csirik, Mihaly Andras; Ruggenthaler, Michael; Rubio, Angel (Peer reviewed; Journal article, 2024)
      We propose exchanging the energy functionals in ground-state density-functional theory with physically equivalent exact force expressions as a new promising route toward approximations to the exchange–correlation potential ...
    • Exchange-only virial relation from the adiabatic connection 

      Laestadius, Andre; Csirik, Mihaly Andras; Penz, Markus; Tancogne-Dejean, Nicolas; Ruggenthaler, Michael; Rubio, Angel; Helgaker, Trygve (Peer reviewed; Journal article, 2024)
      The exchange-only virial relation due to Levy and Perdew is revisited. Invoking the adiabatic connection, we introduce the exchange energy in terms of the right-derivative of the universal density functional w.r.t. the ...
    • Quantum-electrodynamical density-functional theory for the Dicke Hamiltonian 

      Bakkestuen, Vebjørn Hallberg; Csirik, Mihaly Andras; Laestadius, Andre; Penz, Markus (arXiv.org;, Journal article, 2024)
      A detailed analysis of density-functional theory for quantum-electrodynamical model systems is provided. In particular, the quantum Rabi model, the Dicke model, and a generalization of the latter to multiple modes are ...
    • The S-diagnostic - an a posteriori error assessment for single-reference coupled-cluster methods 

      Faulstich, Fabian M.; Kristiansen, Håkon Emil; Csirik, Mihaly Andras; Kvaal, Simen; Pedersen, Thomas Bondo; Laestadius, Andre (Peer reviewed; Journal article, 2023)
      We propose a novel a posteriori error assessment for the single-reference coupled-cluster (SRCC) method called the S-diagnostic. We provide a derivation of the S-diagnostic that is rooted in the mathematical analysis of ...
    • The structure of the density-potential mapping Part I: Standard density-functional theory 

      Penz, Markus; Tellgren, Erik Ingemar; Csirik, Mihaly Andras; Ruggenthaler, Michael; Laestadius, Andre (Peer reviewed; Journal article, 2023)
    • The Structure of the Density-Potential Mapping. Part II: Including Magnetic Fields 

      Penz, Markus; Tellgren, Erik Ingemar; Csirik, Mihaly Andras; Ruggenthaler, Michael; Laestadius, Andre (Peer reviewed; Journal article, 2023)
      The Hohenberg−Kohn theorem of density-functional theory (DFT) is broadly considered the conceptual basis for a full characterization of an electronic system in its ground state by just one-body particle density. In this ...
    • The Structure of the Density-Potential Mapping. Part II: Including Magnetic Fields 

      Penz, Markus; Tellgren, Erik Ingemar; Csirik, Mihaly Andras; Ruggenthaler, Michael; Laestadius, Andre (Peer reviewed; Journal article, 2023)
      The Hohenberg−Kohn theorem of density-functional theory (DFT) is broadly considered the conceptual basis for a full characterization of an electronic system in its ground state by just one-body particle density. In this ...
    • Thermodynamic limit for the magnetic uniform electron gas and representability of density-current pairs 

      Csirik, Mihaly Andras; Laestadius, Andre; Tellgren, Erik (Peer reviewed; Journal article, 2024)
      Although the concept of the uniform electron gas is essential to quantum physics, it has only been defined recently in a rigorous manner by Lewin, Lieb and Seiringer. We extend their approach to include the magnetic case, ...