Simen Kvaal
My background is from physics and applied mathematics, and in 2012 I moved to quantum chemistry. My main interests are analysis and development of computational methods for non-relativistic systems.
I am currently a researcher on Trygve Helgaker's ERC advanced grant ABACUS, where I study formal aspects of density-functional theory. In particular, I study current-density functional theory for molecules in external magnetic fields.
Late 2014, I was awarded an ERC starting grant. The project BIVAQUM dives into the very fundamentals of quantum theory via the so-called bivariational principle. This is a generalization of the standard variational principle that is the foundation for almost every computational scheme for quantum mechanics, and represents a highly unconventional approach, yet it has great potential. The bivariational principle opens up completely new ways of deriving and analyzing methods. In particular, coupled-cluster theory (single- and multireference) may be approached in new ways using the bivariational approach.
BIVAQUM has its own web site, see www.bivaqum.no.
Publications
- Pedersen, Thomas Bondo; Kristiansen, Håkon Emil; Bodenstein, Tilmann; Kvaal, Simen & Schøyen, Øyvind Sigmundson (2021). Interpretation of Coupled-Cluster Many-Electron Dynamics in Terms of Stationary States. Journal of Chemical Theory and Computation. ISSN 1549-9618. 17(1), s 388- 404 . doi: 10.1021/acs.jctc.0c00977 Full text in Research Archive. Show summary
- Bodenstein, Tilmann & Kvaal, Simen (2020). A state-specific multireference coupled-cluster method based on the bivariational principle. Journal of Chemical Physics. ISSN 0021-9606. 153(2) . doi: 10.1063/5.0009429 Full text in Research Archive.
- Kristiansen, Håkon Emil; Schøyen, Øyvind Sigmundson; Kvaal, Simen & Pedersen, Thomas Bondo (2020). Numerical stability of time-dependent coupled-cluster methods for many-electron dynamics in intense laser pulses. Journal of Chemical Physics. ISSN 0021-9606. 152 . doi: 10.1063/1.5142276 Full text in Research Archive.
- Kvaal, Simen; Laestadius, Andre & Bodenstein, Tilmann (2020). Guaranteed convergence for a class of coupled-cluster methods based on Arponen's extended theory. Molecular Physics. ISSN 0026-8976. 118(19-20) . doi: 10.1080/00268976.2020.1810349
- Faulstich, Fabian Maximilian; Laestadius, Andre; Legeza, Örs; Schneider, Reinhold & Kvaal, Simen (2019). Analysis of the Tailored Coupled-Cluster Method in Quantum Chemistry. SIAM Journal on Numerical Analysis. ISSN 0036-1429. 57(6), s 2579- 2607 . doi: 10.1137/18M1171436 Full text in Research Archive.
- Faulstich, Fabian Maximilian; Máté, Mihály; Laestadius, Andre; Csirik, Mihály András; Veis, Libor; Antalik, Andrej; Brabec, Jiří; Schneider, Reinhold; Pittner, Jiří; Kvaal, Simen & Legeza, Örs (2019). Numerical and Theoretical Aspects of the DMRG-TCC Method Exemplified by the Nitrogen Dimer. Journal of Chemical Theory and Computation. ISSN 1549-9618. 15(4), s 2206- 2220 . doi: 10.1021/acs.jctc.8b00960 Show summary
- Laestadius, Andre; Tellgren, Erik; Penz, Markus; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2019). Kohn–Sham Theory with Paramagnetic Currents: Compatibility and Functional Differentiability. Journal of Chemical Theory and Computation. ISSN 1549-9618. 15(7), s 4003- 4020 . doi: 10.1021/acs.jctc.9b00141
- Pedersen, Thomas Bondo & Kvaal, Simen (2019). Symplectic integration and physical interpretation of time-dependent coupled-cluster theory. Journal of Chemical Physics. ISSN 0021-9606. 150 . doi: 10.1063/1.5085390 Full text in Research Archive. Show summary
- Laestadius, Andre & Kvaal, Simen (2018). Analysis of the Extended Coupled-Cluster Method in Quantum Chemistry. SIAM Journal on Numerical Analysis. ISSN 0036-1429. 56(2), s 660- 683 . doi: 10.1137/17M1116611 Full text in Research Archive.
- Laestadius, Andre; Penz, Markus; Tellgren, Erik; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2018). Generalized Kohn-Sham iteration on Banach spaces. Journal of Chemical Physics. ISSN 0021-9606. 149(16), s 1- 9 . doi: 10.1063/1.5037790 Full text in Research Archive.
- Tellgren, Erik; Laestadius, Andre; Helgaker, Trygve; Kvaal, Simen & Teale, Andrew Michael (2018). Uniform magnetic fields in density-functional theory. Journal of Chemical Physics. ISSN 0021-9606. 148(2), s 1- 19 . doi: 10.1063/1.5007300
- Kvaal, Simen & Helgaker, Trygve (2015). Ground-state densities from the Rayleigh-Ritz variation principle and from density-functional theory. Journal of Chemical Physics. ISSN 0021-9606. 143(18) . doi: 10.1063/1.4934797
- Jarlebring, Elias; Kvaal, Simen & Michiels, Wim (2014). An inverse iteration method for eigenvalue problems with eigenvector nonlinearities. SIAM Journal on Scientific Computing. ISSN 1064-8275. 36(4), s A1978- A2001 . doi: 10.1137/130910014
- Kvaal, Simen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2014). Differentiable but exact formulation of density-functional theory. Journal of Chemical Physics. ISSN 0021-9606. 140(18) . doi: 10.1063/1.4867005
- Tellgren, Erik; Kvaal, Simen & Helgaker, Trygve (2014). Fermion N -representability for prescribed density and paramagnetic current density. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 89(1) . doi: 10.1103/PhysRevA.89.012515 Full text in Research Archive.
- Kvaal, Simen (2013). Variational formulations of the coupled-cluster method in quantum chemistry. Molecular Physics. ISSN 0026-8976. 111(9-11), s 1100- 1108 . doi: 10.1080/00268976.2013.812254
- Halvorsen, Tore Gunnar & Kvaal, Simen (2012). Manifestly gauge invariant discretizations of the Schrodinger equation. Physics Letters A. ISSN 0375-9601. 376(12-13), s 1107- 1114 . doi: 10.1016/j.physleta.2012.02.028
- Kvaal, Simen (2012). Ab initio quantum dynamics using coupled-cluster. Journal of Chemical Physics. ISSN 0021-9606. 136(19) . doi: 10.1063/1.4718427
- Tellgren, Erik; Kvaal, Simen; Sagvolden, Espen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2012). Choice of basic variables in current-density-functional theory. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 86(6) . doi: 10.1103/PhysRevA.86.062506 Full text in Research Archive.
- Jarlebring, Elias; Kvaal, Simen & Michiels, Wim (2011). Computing all Pairs (lambda, mu) Such That lambda is a Double Eigenvalue of A + mu B. SIAM Journal on Matrix Analysis and Applications. ISSN 0895-4798. 32, s 902- 927 . doi: 10.1137/100783157 Full text in Research Archive.
- Kvaal, Simen (2011). Multiconfigurational time-dependent Hartree method to describe particle loss due to absorbing boundary conditions. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 84(2) . doi: 10.1103/PhysRevA.84.022512
- Kvaal, Simen; Jarlebring, Elias & Michiels, Wim (2011). Computing singularities of perturbation series. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 83(3) . doi: 10.1103/PhysRevA.83.032505
- Pedersen Lohne, Magnus; Hagen, Gaute; Hjorth-Jensen, Morten; Kvaal, Simen & Pederiva, Francesco (2011). Ab initio computation of the energies of circular quantum dots. Physical Review B. Condensed Matter and Materials Physics. ISSN 1098-0121. 84 . doi: 10.1103/PhysRevB.84.115302 Show summary
- Selstø, Sølve; Birkeland, Tore; Kvaal, Simen; Nepstad, Raymond & Førre, Morten (2011). A master equation approach to double ionization of helium. Journal of Physics B: Atomic, Molecular and Optical Physics. ISSN 0953-4075. 44(21) . doi: 10.1088/0953-4075/44/21/215003
- Hjorth-Jensen, Morten; Dean, David Jarvis; Hagen, G. & Kvaal, Simen (2010). Many-body interactions and nuclear structure. Journal of Physics G: Nuclear and Particle Physics. ISSN 0954-3899. 37(6) . doi: 10.1088/0954-3899/37/6/064035
- Selstø, Sølve & Kvaal, Simen (2010). Absorbing boundary conditions for dynamical many-body quantum systems. Journal of Physics B: Atomic, Molecular and Optical Physics. ISSN 0953-4075. 43(6) . doi: 10.1088/0953-4075/43/6/065004 Full text in Research Archive.
- Kvaal, Simen (2009). Harmonic oscillator eigenfunction expansions, quantum dots, and effective interactions. Physical Review B. Condensed Matter and Materials Physics. ISSN 1098-0121. 80(4) . doi: 10.1103/PhysRevB.80.045321
- Kvaal, Knut; Kucheryavski, Sergei V; Halstensen, Maths; Kvaal, Simen; Flø, Andreas Svarstad; Minkkinen, Pentti & Esbensen, Kim H. (2008). eAMTexplorer: a software package for texture and signal characterization using Angle Measure Technique. Journal of Chemometrics. ISSN 0886-9383. 22(11-12), s 717- 721 . doi: 10.1002/cem.1160 Show summary
- Kvaal, Simen (2008). Geometry of effective Hamiltonians. Physical Review C. Nuclear Physics. ISSN 0556-2813. 78(4) . doi: 10.1103/PhysRevC.78.044330
- Kvaal, Simen; Hjorth-Jensen, Morten & Nilsen, Halvor Møll (2007). Effective interactions, large-scale diagonalization, and one-dimensional quantum dots. Physical Review B. Condensed Matter and Materials Physics. ISSN 1098-0121. 76 . doi: 0.1103/PhysRevB.76.085421 Show summary
- Bodenstein, Tilmann & Kvaal, Simen (2020). A multireference coupled-cluster method based on the bivariational principle.
- Bore, Sigbjørn Løland; Cascella, Michele & Kvaal, Simen (2020). Advances in the Hybrid Particle-Field Approach: Towards Biological Systems. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 2245. Show summary
- Faulstich, Fabian Maximilian; Máté, Mihály; Laestadius, Andre; Csirik, Mihály András; Veis, Libor; Antalik, Andrej; Brabec, Jiří; Schneider, Reinhold; Pittner, Jiří; Kvaal, Simen & Legeza, Örs (2019). Mathematical and numerical aspects of the coupled-cluster method tailored by tensor network states.
- Faulstich, Fabian Maximilian; Máté, Mihály; Laestadius, Andre; Csirik, Mihály András; Veis, Libor; Antalik, Andrej; Brabec, Jiří; Schneider, Reinhold; Pittner, Jiří; Kvaal, Simen & Legeza, Örs (2019). Numerical and theoretical aspects of the DMRG-TCC method exemplified by the nitrogen dimer.
- Laestadius, Andre; Penz, Markus; Tellgren, Erik; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2019). Guaranteed convergence of a regularized Kohn-Sham iteration in finite dimensions. Show summary
- Faulstich, Fabian Maximilian; Laestadius, Andre; Legeza, Örs; Schneider, Reinhold & Kvaal, Simen (2018). Mathematical analysis of the coupled-cluster method tailored by tensor-network states.
- Faulstich, Fabian Maximilian; Laestadius, Andre; Legeza, Örs; Schneider, Reinhold & Kvaal, Simen (2018). Quadratic error bounds for the coupled-cluster method tailored by tensor-network states.
- Laestadius, Andre; Faulstich, Fabian Maximilian; Kvaal, Simen; Legeza, Örs & Schneider, Reinhold (2018). Analysis of The Coupled-Cluster Method Tailored by Tensor-Network States in Quantum Chemistry.
- Laestadius, Andre; Faulstich, Fabian Maximilian; Kvaal, Simen; Legeza, Örs & Schneider, Reinhold (2018). The Study of Coupled-Cluster Methods Using Strong Monotonicity.
- Laestadius, Andre & Kvaal, Simen (2018). ANALYSIS OF THE EXTENDED COUPLED-CLUSTER METHOD IN QUANTUM CHEMISTRY.
- Laestadius, Andre; Penz, Markus; Tellgren, Erik; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2018). Generalized Kohn-Sham iteration on Banach Spaces.
- Pedersen, Thomas Bondo & Kvaal, Simen (2018). Electron Dynamics with Coupled-Cluster Theory.
- Pedersen, Thomas Bondo & Kvaal, Simen (2018). Time-Dependent Coupled-Cluster Theory.
- Tellgren, Erik; Lange, Kai Kaarvann; Sagvolden, Espen; Kvaal, Simen; Austad, Jon; Reimann, Sarah; Borgoo, Alex; Fliegl, Heike; Sen, Sangita & Helgaker, Trygve (2018). Quantum chemistry for strong magnetic fields.
- Faulstich, Fabian Maximilian; Laestadius, Andre; Legeza, Örs; Schneider, Reinhold & Kvaal, Simen (2017). Mathematical aspects of the coupled-cluster method tailored by tensor-network states in quantum chemistry.
- Kvaal, Simen & Laestadius, Andre (2016). The extended coupled-cluster method and its rigorous analysis.
- Laestadius, Andre & Kvaal, Simen (2016). Analysis of the Extended Coupled-Cluster Method.
- Tellgren, Erik; Teale, Andrew Michael; Ekström, Ulf Egil; Kvaal, Simen; Sagvolden, Espen & Helgaker, Trygve (2015). Current density functional theory for molecular systems in strong magnetic fields.
- Helgaker, Trygve; Borgoo, Alex; Ekström, Ulf Egil; Furness, James; Hoffmann, Mark; Kvaal, Simen; Lange, Kai Kaarvann; Reimann, Sarah; Sagvolden, Espen; Stopkowicz, Stella; Tellgren, Erik & Teale, Andrew Michael (2014). Density-Functional Theory in Magnetic Fields.
- Helgaker, Trygve; Kvaal, Simen; Ekström, Ulf Egil & Teale, Andrew Michael (2014). Differentiable but Exact Formulation of Density-Functional Theory.
- Helgaker, Trygve; Kvaal, Simen; Ekström, Ulf Egil & Teale, Andy (2014). Differentiable but Exact Formulation of Density-Functional Theory.
- Helgaker, Trygve; Kvaal, Simen; Teale, Andrew Michael & Ekström, Ulf Egil (2014). Differentiable but Exact Formulation of Density-Functional Theory.
- Helgaker, Trygve; Kvaal, Simen; Teale, Andrew Michael; Ekström, Ulf Egil; Jørgensen, Poul & Olsen, Jeppe (2014). Differentiable but Exact Formulation of Density-Functional Theory.
- Kvaal, Simen (2014). Bivariational approximations & the orbital-adaptive coupled-cluster method.
- Sagvolden, Espen; Tellgren, Erik; Kvaal, Simen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2013). Building blocks of Current Density Functional Theory.
- Ekström, Ulf Egil; Kvaal, Simen; Borgoo, Alex; Helgaker, Trygve; Sagvolden, Espen & Tellgren, Erik (2013). Moreau-Yosida regularization of DFT.
- Kvaal, Simen (2013). Ab initio dynamics using the coupled cluster method.
- Kvaal, Simen (2013, 24. mai). Abels Tårn. [Radio]. NRK P2.
- Kvaal, Simen; Ekström, Ulf Egil; Tellgren, Erik; Borgoo, Alex; Helgaker, Trygve & Sagvolden, Espen (2013). Moreau-Yosida regularization of DFT.
- Sagvolden, Espen; Tellgren, Erik; Kvaal, Simen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2013). Building blocks of Current Density Functional Theory.
- Selstø, Sølve; Kvaal, Simen; Birkeland, Tore; Nepstad, Raymond & Førre, Morten (2012). Double ionization with absorbers. EurophysicsNews. ISSN 0531-7479. 43(1), s 15- 16
- Kvaal, Simen (2010). Adaptive time-dependent coupled cluster method for wave-packet propagation of many-fermion systems.
- Kvaal, Simen (2010). Time-dependent Coupled Cluster for Many-Body Quantum Dynamics.
- Kvaal, Simen (2010). Time-dependent coupled-cluster approach to many-body quantum dynamics.
- Kvaal, Simen (2010). Variational Principles for Coupled-Cluster Methods.
- Kvaal, Simen; Jarlebring, Elias & Michiels, Wim (2010). A numerical method for computing the radius of convergence of Rayleigh Schroedinger Perturbation theory without the need for the terms in the series.
- Selstø, Sølve; Førre, Morten; Kvaal, Simen; Nepstad, Raymond & Birkeland, Tore (2010). Describing double photo-ionization of helium bymeans of absorbing boundaries.
- Selstø, Sølve & Kvaal, Simen (2010). Absorbing boundaries for more than one particle.
- Selstø, Sølve & Kvaal, Simen (2010). Absorbing boundary conditions for dynamical many-particles systems.
- Selstø, Sølve; Kvaal, Simen; Nepstad, Raymond & Førre, Morten (2010). Non-sequential double ionization of helium: Extracting the cross section.
- Halvorsen, Tore Gunnar & Kvaal, Simen (2009). Manifestly gauge invariant discretizations of the Schrödinger equation.
- Hjorth-Jensen, Morten & Kvaal, Simen (2009). Effective interactions and convergence criteria for configuration interaction methods.
- Jarlebring, Elias; Kvaal, Simen & Michiels, Wim (2009). Computing all pairs (lambda,mu) such that lambda is a double eigenvalue of A + mu B. Full text in Research Archive. Show summary
- Kvaal, Simen (2009). Analysis of many-body methods for quantum dots.
- Kvaal, Simen (2009). Rigorous analysis of ab initio calculations for parabolic quantum dots. Full text in Research Archive.
- Kvaal, Simen (2009). Usynlig Verden.
- Kvaal, Simen & Halvorsen, Tore Gunnar (2009). One gauge to rule them all -- Gauge-invariant grid discretizations.
- Hjorth-Jensen, Morten & Kvaal, Simen (2007). Similarity Transformations, Flow Equations and Many-Body Perturbation Theory: Role of Many-Body Forces.