A5010744478- Spectroscopy and Quantum Chemical Studies
- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Advanced Chemical Physics Studies
- Molecular spectroscopy and chirality
- Genetics, Bioinformatics, and Biomedical Research
- Bioinformatics and Genomic Networks
- Advanced NMR Techniques and Applications
- Computational Physics and Python Applications
- Inorganic Fluorides and Related Compounds
- Neural Networks and Reservoir Computing
- Electrochemical Analysis and Applications
- Hydrocarbon exploration and reservoir analysis
- Chemical Synthesis and Analysis
- CO2 Sequestration and Geologic Interactions
- Machine Learning in Materials Science
- Physics of Superconductivity and Magnetism
- DNA and Nucleic Acid Chemistry
- Nuclear Physics and Applications
- Quantum optics and atomic interactions
- Protein Structure and Dynamics
- Quantum, superfluid, helium dynamics
- Nanomaterials for catalytic reactions
- Molecular Junctions and Nanostructures
University of Southern Denmark
2015-2025
Aalborg University
2019
UiT The Arctic University of Norway
2019
The Dalton Project provides a uniform platform access to the underlying full-fledged quantum chemistry codes and LSDalton as well PyFraME package for automatized fragmentation parameterization of complex molecular environments. is written in Python defines means library communication interaction. Intermediate data such integrals are exposed made accessible user form NumPy arrays, resulting extracted, analyzed, visualized. Complex computational protocols that may, instance, arise due need...
Determining the properties of molecules and materials is one premier applications quantum computing. A major question in field how to use imperfect near-term computers solve problems practical value. Inspired by recently developed variants counterpart equation-of-motion (qEOM) approach orbital-optimized variational eigensolver (oo-VQE), we present a algorithm (oo-VQE-qEOM) for calculation molecular computing expectation values on computer. We perform noise-free simulations BeH2 series...
Linear response (LR) theory is a powerful tool in classic quantum chemistry crucial to understanding photoinduced processes and biology. However, performing simulations for large systems the case of strong electron correlation remains challenging. Quantum computers are poised facilitate simulation such systems, recently, linear formulation (qLR) was introduced [Kumar et al., J. Chem. Theory Comput. 2023, 19, 9136–9150]. To apply qLR near-term beyond minimal basis set, we here introduce...
We explore Davidson methods for obtaining excitation energies and other linear response properties within the recently developed quantum self-consistent (q-sc-LR) method. Davidson-type allow only a few selected without explicitly constructing electronic Hessian since they require ability to perform Hessian-vector multiplications. apply method calculate of hydrogen chains (up H10) analyze aspects statistical noise computing on simulators. Additionally, we such as static polarizabilities H2,...
We formulate and implement the Variational Quantum Eigensolver Self Consistent Field (VQE-SCF) algorithm in combination with polarizable embedding (PE), thereby extending PE to regime of quantum computing. test resulting algorithm, PE-VQE-SCF, on simulators demonstrate that computational stress device is only slightly increased terms gate counts compared regular VQE-SCF. On other hand, no increase shot noise was observed. illustrate how PE-VQE-SCF may lead modeling real chemical systems...
The promise of quantum computing to circumvent the exponential scaling chemistry has sparked a race develop algorithms for architecture. However, most works neglect quantum-inherent shot noise, let alone effect current noisy devices. Here, we present comprehensive study linear response (qLR) theory obtaining spectroscopic properties on simulated fault-tolerant computers and present-day near-term hardware. This work introduces novel metrics analyze predict origins noise in algorithm, proposes...
We present the theory and implementation of a fully variational wave function–density functional (DFT) hybrid model, which is applicable to many cases strong correlation. denote this model as multiconfigurational self-consistent on-top pair-density (MC-srPDFT) model. have previously shown how short-range DFT (MC-srDFT) can describe any spin symmetry also state-specific calculations on excited states [Hedegård et al., J. Chem. Phys. 148(21), 214103 (2018)]. However, srDFT part MC-srDFT has...
Quantum computing presents a promising avenue for solving complex problems, particularly in quantum chemistry, where it could accelerate the computation of molecular properties and excited states. This work focuses on excitation energies with hybrid quantum-classical algorithms near-term devices, combining linear response (qLR) method polarizable embedding (PE) environment. We employ self-consistent operator manifold (q-sc-LR) top unitary coupled cluster (UCC) wave function combination...
Quantum chemistry embedding methods have become a popular approach to calculate molecular properties of larger systems. In order account for finite temperature effects, including both configurational and conformational averaging, are often combined with dynamics (MD) simulations either in direct or sequential manner. One the decisive factors successful application is that underlying structures provided by MD simulation accurate, if not this will result low-quality prediction question. Here...
We present a modular open-source library for polarizable embedding (PE) named CPPE. The is implemented in C++, and it additionally provides Python interface rapid prototyping experimentation high-level scripting language. Our integrates seamlessly with existing quantum chemical program packages through an intuitive minimal interface. Until now, CPPE has been interfaced to three packages, Q-Chem, Psi4, PySCF. Furthermore, we show action using all computational spectroscopy application. With...
We test the performance of Polarizable Embedding Variational Quantum Eigensolver Self-Consistent-Field (PE-VQE-SCF) model for computing electric field gradients with comparisons to conventional complete active space self-consistent-field (CASSCF) calculations and experimental results. compute quadrupole coupling constants ice VIII IX. find that inclusion environment is crucial obtaining results match data. The are within uncertainty both CASSCF VQE-SCF oxygen lie close value IX as well. With...
The prediction of spectral properties via linear response (LR) theory is an important tool in quantum chemistry for understanding photoinduced processes molecular systems. With the advances computing, we recently adapted this method near-term hardware using a truncated active space approximation with orbital rotation, named (qLR). In effort to reduce classic cost hybrid approach, here derive and implement reduced density matrix (RDM) driven approach qLR. This allows calculation moderately...
The promise of quantum computing to circumvent the exponential scaling chemistry has sparked a race develop algorithms for architecture. However, most works neglect quantum-inherent shot noise, let alone effect current noisy devices. Here, we present comprehensive study linear response (qLR) theory obtaining spectroscopic properties on simulated fault-tolerant computers and present-day near-term hardware. This work introduces novel metrics analyze predict origins noise in algorithm, proposes...
Calculating molecular properties using quantum devices can be performed through the linear response (qLR) or, equivalently, equation of motion (qEOM) formulations. Different parameterizations qLR and qEOM are available, namely naïve, projected, self-consistent, state-transfer. In naïve projected parameterizations, metric is not identity, we show that it depends on redundant orbital rotations. This dependency may lead to divergences in excitation energies for certain choices rotation...
We present the theory and implementation of a novel, fully variational wave function - density functional (DFT) hybrid model, which is applicable to many cases strong correlation. denote this model multiconfigurational self-consistent on-top pair-density (MC-srPDFT). have previously shown how multi-configurational short-range DFT (MC-srDFT) can describe any spin symmetry, also state-specific calculations on excited states. However, srDFT part MC-srDFT has some deficiencies that it shares...
The fragment-based polarizable embedding (PE) model combined with an appropriate electronic structure method constitutes a highly efficient and accurate multiscale approach for computing spectroscopic properties of central moiety including effects from its molecular environment through potential. There is, however, comparatively high computational overhead associated the computation potential, which is derived first-principles calculations on individual fragments environment. To reduce cost...
Linear response theory for the multiconfigurational short-range density functional (MC–srDFT) model is extended to triplet with a singlet reference wave function. The linear equations MC–srDFT are derived general hybrid srGGA and implemented in Dalton program. Triplet excitation energies benchmarked against CC3 of coupled cluster complete-active-space second-order perturbation using three different functionals (srLDA, srPBE, srPBE0), both full employing generalized Tamm-Dancoff approximation...
The multi-configurational short-range (sr) density functional theory has been extended to the calculation of indirect spin–spin coupling constants (SSCCs) for nuclear magnetic resonance spectroscopy. performance new method is compared Kohn–Sham and ab initio complete active space self-consistent field a selected set molecules with good reference values. Two functionals have considered, local approximation srLDA srPBE from GGA class functionals. All srDFT calculations are Hartree–Fock-type...
In this paper, we present the theory and implementation of nuclear magnetic resonance shielding constants with gauge-including atomic orbitals for hybrid multiconfigurational short-range density functional model. As a special case, also includes Hartree-Fock srDFT (HF-srDFT). Choosing complete-active space (CAS) wave function as parameterization function, investigate how well CAS-srDFT reproduces experimental trends compared to DFT complete active self-consistent field (CASSCF). Calculations...
We explore Davidson methods for obtaining excitation energies and other linear response properties within quantum self-consistent (q-sc-LR) theory. Davidson-type allow only a few selected without explicitly constructing the electronic Hessian since they require ability to perform Hessian-vector multiplications. apply method calculate of hydrogen chains (up H$_{10}$) analyze aspects statistical noise computing on simulators. Additionally, we such as static polarizabilities H$_2$, LiH, H$_2$O,...
The prediction of spectral properties via linear response (LR) theory is an important tool in quantum chemistry for understanding photo-induced processes molecular systems. With the advances computing, we recently adapted this method near-term hardware using a truncated active space approximation with orbital rotation, named (qLR). In effort to reduce classic cost hybrid approach, here derive and implement reduced density matrix (RDM) driven approach qLR. This allows calculation moderately...
Calculating molecular properties using quantum devices can be done through the linear response (qLR) or, equivalently, equation of motion (qEOM) formulations. Different parameterizations qLR and qEOM are available, namely naive, projected, self-consistent, state-transfer. In naive projected parameterizations, metric is not identity, we show that it depends on redundant orbital rotations. This dependency may lead to divergences in excitation energies for certain choices rotation parameters an...
We test the performance of polarizable embedding variational quantum eigensolver self-consistent field (PE-VQE-SCF) model for computing electric gradients with comparisons to conventional complete active space self-consistent-field (CASSCF) calculations and experimental results. compute quadrupole coupling constants ice VIII IX. find close agreement quantum-computing PE-VQE-SCF results from classical PE-CASSCF experiment. Furthermore, we observe that inclusion environment is crucial...