List of publications
49 peer-reviewed journal articles in mathematics, physics, and chemistry
1 published book chapter
6 single-author papers (2008–2023)
1,835 citations · h-index 22
Peer-Reviewed Journal Articles
2026
- Einar Aurbakken, Håkon Emil Kristiansen, Simen Kvaal, Antoine Camper, and Thomas Bondo Pedersen (2026). Ultrafast laser-driven quantum dynamics in positronium chloride. The Journal of Chemical Physics, 165(8), 084307.
doi:10.1063/5.0335998
2025
Simen Kvaal, Håkon Richard Fredheim, Mads Greisen Højlund, and Thomas Bondo Pedersen (2025). Time-dependent Bivariational Principle: Theoretical Foundation for Real-Time Propagation Methods of Coupled-Cluster Type. The Journal of Physical Chemistry A, 129(15), 3508–3521.
doi:10.1021/acs.jpca.4c07417Simon Elias Schrader, Håkon Emil Kristiansen, Thomas Bondo Pedersen, and Simen Kvaal (2025). Time-Dependent Gaussian Basis Sets for Many-Body Systems Using Rothe’s Method: A Mean-Field Study. Journal of Chemical Theory and Computation, 21(17), 8490–8508.
doi:10.1021/acs.jctc.5c00970Aleksander P. Woźniak, Ludwik Adamowicz, Thomas Bondo Pedersen, and Simen Kvaal (2025). Rothe Time Propagation for Coupled Electronic and Rovibrational Quantum Dynamics. The Journal of Physical Chemistry A, 129(24), 5391–5404.
doi:10.1021/acs.jpca.5c01732Simon Elias Schrader, Thomas Bondo Pedersen, and Simen Kvaal (2025). Multidimensional quantum dynamics with explicitly correlated Gaussian wave packets using Rothe’s method. The Journal of Chemical Physics, 162(2), 024109.
doi:10.1063/5.0247732Håkon Emil Kristiansen, Håkon Kvernmoen, Simen Kvaal, and Thomas Bondo Pedersen (2025). Configuration Weights in Coupled-Cluster Theory. The Journal of Physical Chemistry A, 129(10), 2638–2654.
doi:10.1021/acs.jpca.4c07443
2024
Einar Aurbakken, Benedicte Sverdrup Ofstad, Håkon Emil Kristiansen, Øyvind Sigmundson Schøyen, Simen Kvaal, Lasse Kragh Sørensen, Roland Lindh, and Thomas Bondo Pedersen (2024). Transient spectroscopy from time-dependent electronic-structure theory without multipole expansions. Physical Review A, 109(1), 013109.
doi:10.1103/PhysRevA.109.013109Simon Elias Schrader, Håkon Emil Kristiansen, Thomas Bondo Pedersen, and Simen Kvaal (2024). Time evolution as an optimization problem: The hydrogen atom in strong laser fields in a basis of time-dependent Gaussian wave packets. The Journal of Chemical Physics, 161(4), 044105.
doi:10.1063/5.0213576Aleksander P. Woźniak, Ludwik Adamowicz, Thomas Bondo Pedersen, and Simen Kvaal (2024). Gaussians for Electronic and Rovibrational Quantum Dynamics. The Journal of Physical Chemistry A, 128(18), 3659–3671.
doi:10.1021/acs.jpca.4c00364
2023
Benedicte Sverdrup Ofstad, Einar Aurbakken, Øyvind Sigmundson Schøyen, Håkon Emil Kristiansen, Simen Kvaal, and Thomas Bondo Pedersen (2023). Time-dependent coupled-cluster theory. WIREs Computational Molecular Science, 13(5), e1666.
doi:10.1002/wcms.1666Simen Kvaal (2023). Three Lagrangians for the complete-active space coupled-cluster method. The Journal of Chemical Physics, 158(24), 244113.
doi:10.1063/5.0148988Fabian M. Faulstich, Håkon E. Kristiansen, Mihály A. Csirik, Simen Kvaal, Thomas Bondo Pedersen, and Andre Laestadius (2023). S-Diagnostic—An a Posteriori Error Assessment for Single-Reference Coupled-Cluster Methods. The Journal of Physical Chemistry A, 127(43), 9106–9120.
doi:10.1021/acs.jpca.3c01575Simen Kvaal (2023). Moreau–Yosida Regularization in DFT. In Eric Cancès and Gero Friesecke (Eds.), Density Functional Theory: Modeling, Mathematical Analysis, Computational Methods, and Applications (pp. 267–306). Springer International Publishing.
doi:10.1007/978-3-031-22340-2_5Benedicte Sverdrup Ofstad, Meilani Wibowo-Teale, Håkon Emil Kristiansen, Einar Aurbakken, Marios Petros Kitsaras, Øyvind Sigmundson Schøyen, Eirill Hauge, Tom J. P. Irons, Simen Kvaal, Stella Stopkowicz, Andrew M. Wibowo-Teale, and Thomas Bondo Pedersen (2023). Magnetic optical rotation from real-time simulations in finite magnetic fields. The Journal of Chemical Physics, 159(20), 204109.
doi:10.1063/5.0171927Benedicte Sverdrup Ofstad, Håkon Emil Kristiansen, Einar Aurbakken, Øyvind Sigmundson Schøyen, Simen Kvaal, and Thomas Bondo Pedersen (2023). Adiabatic extraction of nonlinear optical properties from real-time time-dependent electronic-structure theory. The Journal of Chemical Physics, 158(15), 154102.
doi:10.1063/5.0145521Simon Elias Schrader and Simen Kvaal (2023). Accelerated coupled cluster calculations with Procrustes orbital interpolation. The Journal of Chemical Physics, 158(11), 114116.
doi:10.1063/5.0141145
2022
Håkon Emil Kristiansen, Benedicte Sverdrup Ofstad, Eirill Hauge, Einar Aurbakken, Øyvind Sigmundson Schøyen, Simen Kvaal, and Thomas Bondo Pedersen (2022). Linear and Nonlinear Optical Properties from TDOMP2 Theory. Journal of Chemical Theory and Computation, 18(6), 3687–3702.
doi:10.1021/acs.jctc.1c01309Ludwik Adamowicz, Simen Kvaal, Caroline Lasser, and Thomas Bondo Pedersen (2022). Laser-induced dynamic alignment of the HD molecule without the Born–Oppenheimer approximation. The Journal of Chemical Physics, 157(14), 144302.
doi:10.1063/5.0101352Andrew M. Teale, Trygve Helgaker, Andreas Savin, Carlo Adamo, Bálint Aradi, Alexei V. Arbuznikov, Paul W. Ayers, Evert Jan Baerends, Vincenzo Barone, Patrizia Calaminici, Eric Cancès, Emily A. Carter, Pratim Kumar Chattaraj, Henry Chermette, Ilaria Ciofini, T. Daniel Crawford, Frank De Proft, John F. Dobson, Claudia Draxl, Thomas Frauenheim, Emmanuel Fromager, Patricio Fuentealba, Laura Gagliardi, Giulia Galli, Jiali Gao, Paul Geerlings, Nikitas Gidopoulos, Peter M. W. Gill, Paola Gori-Giorgi, Andreas Görling, Tim Gould, Stefan Grimme, Oleg Gritsenko, Hans Jørgen Aagaard Jensen, Erin R. Johnson, Robert O. Jones, Martin Kaupp, Andreas M. Köster, Leeor Kronik, Anna I. Krylov, Simen Kvaal, Andre Laestadius, Mel Levy, Mathieu Lewin, Shubin Liu, Pierre-François Loos, Neepa T. Maitra, Frank Neese, John P. Perdew, Katarzyna Pernal, Pascal Pernot, Piotr Piecuch, Elisa Rebolini, Lucia Reining, Pina Romaniello, Adrienn Ruzsinszky, Dennis R. Salahub, Matthias Scheffler, Peter Schwerdtfeger, Viktor N. Staroverov, Jianwei Sun, Erik Tellgren, David J. Tozer, Samuel B. Trickey, Carsten A. Ullrich, Alberto Vela, Giovanni Vignale, Tomasz A. Wesolowski, Xin Xu, and Weitao Yang (2022). DFT exchange: sharing perspectives on the workhorse of quantum chemistry and materials science. Physical Chemistry Chemical Physics, 24(47), 28700–28781.
doi:10.1039/D2CP02827A
2021
Simen Kvaal, Andre Laestadius, Erik Tellgren, and Trygve Helgaker (2021). Lower Semicontinuity of the Universal Functional in Paramagnetic Current–Density Functional Theory. The Journal of Physical Chemistry Letters, 12(5), 1421–1425.
doi:10.1021/acs.jpclett.0c03422Thomas Bondo Pedersen, Håkon Emil Kristiansen, Tilmann Bodenstein, Simen Kvaal, and Øyvind Sigmundson Schøyen (2021). Interpretation of Coupled-Cluster Many-Electron Dynamics in Terms of Stationary States. Journal of Chemical Theory and Computation, 17(1), 388–404.
doi:10.1021/acs.jctc.0c00977
2020
Håkon Emil Kristiansen, Øyvind Sigmundson Schøyen, Simen Kvaal, and Thomas Bondo Pedersen (2020). Numerical stability of time-dependent coupled-cluster methods for many-electron dynamics in intense laser pulses. The Journal of Chemical Physics, 152(7), 071102.
doi:10.1063/1.5142276Simen Kvaal, Andre Laestadius, and Tilmann Bodenstein (2020). Guaranteed convergence for a class of coupled-cluster methods based on Arponen’s extended theory. Molecular Physics, 118(19-20), e1810349.
doi:10.1080/00268976.2020.1810349Tilmann Bodenstein and Simen Kvaal (2020). A state-specific multireference coupled-cluster method based on the bivariational principle. The Journal of Chemical Physics, 153(2), 024106.
doi:10.1063/5.0009429
2019
Thomas Bondo Pedersen and Simen Kvaal (2019). Symplectic integration and physical interpretation of time-dependent coupled-cluster theory. The Journal of Chemical Physics, 150(14), 144106.
doi:10.1063/1.5085390Fabian M. Faulstich, Mihály Máté, Andre Laestadius, Mihály András Csirik, Libor Veis, Andrej Antalík, Jiří Brabec, Reinhold Schneider, Jiří Pittner, Simen Kvaal, and Örs Legeza (2019). Numerical and Theoretical Aspects of the DMRG-TCC Method Exemplified by the Nitrogen Dimer. Journal of Chemical Theory and Computation, 15(4), 2206–2220.
doi:10.1021/acs.jctc.8b00960Andre Laestadius, Erik I. Tellgren, Markus Penz, Michael Ruggenthaler, Simen Kvaal, and Trygve Helgaker (2019). Kohn–Sham Theory with Paramagnetic Currents: Compatibility and Functional Differentiability. Journal of Chemical Theory and Computation, 15(7), 4003–4020.
doi:10.1021/acs.jctc.9b00141Fabian M. Faulstich, Andre Laestadius, Örs Legeza, Reinhold Schneider, and Simen Kvaal (2019). Analysis of the Tailored Coupled-Cluster Method in Quantum Chemistry. SIAM Journal on Numerical Analysis, 57(6), 2579–2607.
doi:10.1137/18M1171436
2018
Erik I. Tellgren, Andre Laestadius, Trygve Helgaker, Simen Kvaal, and Andrew M. Teale (2018). Uniform magnetic fields in density-functional theory. The Journal of Chemical Physics, 148(2), 024101.
doi:10.1063/1.5007300Andre Laestadius, Markus Penz, Erik I. Tellgren, Michael Ruggenthaler, Simen Kvaal, and Trygve Helgaker (2018). Generalized Kohn–Sham iteration on Banach spaces. The Journal of Chemical Physics, 149(16), 164103.
doi:10.1063/1.5037790Andre Laestadius and Simen Kvaal (2018). Analysis of the Extended Coupled-Cluster Method in Quantum Chemistry. SIAM Journal on Numerical Analysis, 56(2), 660–683.
doi:10.1137/17M1116611
2015
- Simen Kvaal and Trygve Helgaker (2015). Ground-state densities from the Rayleigh–Ritz variation principle and from density-functional theory. The Journal of Chemical Physics, 143(18), 184106.
doi:10.1063/1.4934797
2014
Erik I. Tellgren, Simen Kvaal, and Trygve Helgaker (2014). Fermion N-representability for prescribed density and paramagnetic current density. Physical Review A, 89(1), 012515.
doi:10.1103/PhysRevA.89.012515Simen Kvaal, Ulf Ekström, Andrew M. Teale, and Trygve Helgaker (2014). Differentiable but exact formulation of density-functional theory. The Journal of Chemical Physics, 140(18), 18A518.
doi:10.1063/1.4867005Elias Jarlebring, Simen Kvaal, and Wim Michiels (2014). An Inverse Iteration Method for Eigenvalue Problems with Eigenvector Nonlinearities. SIAM Journal on Scientific Computing, 36(4), A1978–A2001.
doi:10.1137/130910014
2013
- Simen Kvaal (2013). Variational formulations of the coupled-cluster method in quantum chemistry. Molecular Physics, 111(9-11), 1100–1108.
doi:10.1080/00268976.2013.812254
2012
Tore Gunnar Halvorsen and Simen Kvaal (2012). Manifestly gauge invariant discretizations of the Schrödinger equation. Physics Letters A, 376(12-13), 1107–1114.
doi:10.1016/j.physleta.2012.02.028Erik I. Tellgren, Simen Kvaal, Espen Sagvolden, Ulf Ekström, Andrew M. Teale, and Trygve Helgaker (2012). Choice of basic variables in current-density-functional theory. Physical Review A, 86(6), 062506.
doi:10.1103/PhysRevA.86.062506Simen Kvaal (2012). Ab initio quantum dynamics using coupled-cluster. The Journal of Chemical Physics, 136(19), 194109.
doi:10.1063/1.4718427
2011
Simen Kvaal (2011). Multiconfigurational time-dependent Hartree method to describe particle loss due to absorbing boundary conditions. Physical Review A, 84(2), 022512.
doi:10.1103/PhysRevA.84.022512Simen Kvaal, Elias Jarlebring, and Wim Michiels (2011). Computing singularities of perturbation series. Physical Review A, 83(3), 032505.
doi:10.1103/PhysRevA.83.032505Elias Jarlebring, Simen Kvaal, and Wim Michiels (2011). Computing all Pairs (λ, μ) Such That λ is a Double Eigenvalue of A+μB. SIAM Journal on Matrix Analysis and Applications, 32(3), 902–927.
doi:10.1137/100783157M. Pedersen Lohne, Gaute Hagen, Morten Hjorth-Jensen, Simen Kvaal, and F. Pederiva (2011). Ab initio computation of the energies of circular quantum dots. Physical Review B, 84(11), 115302.
doi:10.1103/PhysRevB.84.115302Sølve Selstø, Tore Birkeland, Simen Kvaal, Raymond Nepstad, and Morten Førre (2011). A master equation approach to double ionization of helium. Journal of Physics B: Atomic, Molecular and Optical Physics, 44(21), 215003.
doi:10.1088/0953-4075/44/21/215003
2010
Morten Hjorth-Jensen, David J. Dean, Gaute Hagen, and Simen Kvaal (2010). Many-body interactions and nuclear structure. Journal of Physics G: Nuclear and Particle Physics, 37(6), 064035.
doi:10.1088/0954-3899/37/6/064035Sølve Selstø and Simen Kvaal (2010). Absorbing boundary conditions for dynamical many-body quantum systems. Journal of Physics B: Atomic, Molecular and Optical Physics, 43(6), 065004.
doi:10.1088/0953-4075/43/6/065004
2009
- Simen Kvaal (2009). Harmonic oscillator eigenfunction expansions, quantum dots, and effective interactions. Physical Review B, 80(4), 045321.
doi:10.1103/PhysRevB.80.045321
2008
Knut Kvaal, Sergei V. Kucheryavski, Maths Halstensen, Simen Kvaal, Andreas S. Flø, Pentti Minkkinen, and Kim H. Esbensen (2008). eAMTexplorer: a software package for texture and signal characterization using Angle Measure Technique. Journal of Chemometrics, 22(11-12), 717–721.
doi:10.1002/cem.1160Simen Kvaal (2008). Geometry of effective Hamiltonians. Physical Review C, 78(4), 044330.
doi:10.1103/PhysRevC.78.044330
2007
- Simen Kvaal, Morten Hjorth-Jensen, and Halvor Møll Nilsen (2007). Effective interactions, large-scale diagonalization, and one-dimensional quantum dots. Physical Review B, 76(8), 085421.
doi:10.1103/PhysRevB.76.085421
Preprints
2026
Rothe’s Method for Quantum Dynamics in Atoms and Molecules with Gaussian Wavepackets
Simon Elias Schrader, Håkon Emil Kristiansen, Aleksander P. Wozniak, Ludwik Adamowicz, Simen Kvaal, and Thomas Bondo Pedersen (2026).
doi:10.48550/arXiv.2606.20947
Abstract
Capable of capturing both bound and continuum quantum dynamics, Gaussian wavepackets are highly attractive basis functions for simulating laser-driven processes in atoms and molecules. Unfortunately, fully flexible Gaussian wavepackets are exceedingly challenging to propagate in a numerically stable manner within the framework of conventional time-dependent variational principles. In this chapter, we discuss the sources of the numerical issues and review an alternative approach, Rothe’s method, that offers a route to improved numerical stability. Recent proof-of-concept simulations based on Rothe’s method indicate that Gaussian wavepackets provide results on par with highly accurate grid-based methods for both electronic and rovibrational quantum dynamics, including ultrafast nonlinear processes that involve the continuum such as high-harmonic generation. Remarkably few Gaussian wavepackets are needed to achieve the high accuracy of grid-based approaches, indicating that further algorithmic developments and efficient implementations may enable efficient simulations of not only electronic and rovibrational phenomena but also fully coupled electronic-nuclear quantum dynamics with significantly reduced memory demands. We also point out remaining practical challenges, including matrix elements of the squared Hamiltonian and the treatment of Coulomb cusps.
Reduced Density Matrix Functional Theory And A Reduced Formulation Of Density Functional Theory
Håkon R. Fredheim and Simen Kvaal (2026).
doi:10.48550/arXiv.2510.12242
Abstract
A mathematical framework for reduced density matrix functional theory (RDMFT) is proposed. The work is inspired by and generalizes the work by E.H. Lieb [E.H. Lieb, Int. J. Quant. Chem. 24(1983), pp.243–277] on density-functional theory (DFT). We introduce a Banach space for density matrices with finite kinetic energy. The dual space is a rich class of single-particle potentials, i.e., Hermitian forms. The ground state energy of an \(N\)-fermion system with external forces given by any such Hermitian form is expressed as the Legendre–Fenchel transform of a convex and lower semicontinuous “universal” reduced density matrix functional. The formalism is employed to provide a mathematical framework for density-functional theory (DFT). The main tool here is a rigorous definition of diagonals of reduced density matrices. The result is a refinement of Lieb’s results on DFT applicable to a wide variety of models.
2022
No need for a grid: Adaptive fully-flexible gaussians for the time-dependent Schrödinger equation
Simen Kvaal, Caroline Lasser, Thomas Bondo Pedersen, and Ludwik Adamowicz (2022).
arXiv
Abstract
Linear combinations of complex gaussian functions, where the nonlinear parameters are allowed to vary, are shown to be an extremely flexible representation for the solution of the time-dependent Schrödinger equation in one spatial dimension. Propagation of such wavefunctions using the Dirac–Frenkel variational principle is notoriously hard, and we present instead a scheme based on the method of vertical lines, or Rothe’s method. We apply the method to a simple test system mimicking an atom subject to an extreme laser pulse, producing complicated ionization dynamics. The scheme is shown to perform very well on this model. Since the propagation method can be formulated entirely in terms of gaussian integrals and expectation values, we eliminate the need for large grids using only a handful of gaussian functions but with the same accuracy. This paves the way for accurate and affordable solutions of the time-dependent Schrödinger equation for multi-atom molecules beyond the Born–Oppenheimer approximation.