Vibronic Structure of the UV/Visible Absorption Spectra of Phenol and Phenolate: A Hybrid Density Functional Theory─Doktorov’s Quantum Algorithm Approach DOI
R. Hernández, Armand Soldera, Benoı̂t Champagne

et al.

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 24, 2024

The Doktorov's quantum algorithm has been enacted in combination with time-dependent density functional theory (TD-DFT) to simulate the vibronic structure of UV/visible absorption spectra phenol and phenolate molecules. On one hand, DFT TD-DFT are employed classical algorithms calculate ground excited-state electronic structures as well their vibrational frequencies normal modes, whereas, on other for evaluating transition intensities. In comparison a previous study, J. Phys. Chem. A 2024, 128, 4369–4377, which demonstrated proof concept predict ionization spectra, it is applied here medium-size molecules more than 30 without accounting Duschinsky rotations due software limitations. This application also enables assessing impact differences between excited states.

Language: Английский

Understanding and mitigating noise in molecular quantum linear response for spectroscopic properties on quantum computers DOI Creative Commons
Karl Michael Ziems, Erik Rosendahl Kjellgren, Stephan P. A. Sauer

et al.

Chemical Science, Journal Year: 2025, Volume and Issue: 16(10), P. 4456 - 4468

Published: Jan. 1, 2025

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 an Ansatz-based error mitigation technique, reveals significant impact Pauli saving reducing measurement costs subspace methods. Our hardware results using up cc-pVTZ basis set serve as proof principle absorption spectra general approach with accuracy classical multi-configurational Importantly, our exemplify that substantial improvements rates speed are necessary lift computational from concept actual field.

Language: Английский

Citations

1
Which Options Exist for NISQ-Friendly Linear Response Formulations? DOI
Karl Michael Ziems, Erik Rosendahl Kjellgren, Peter Reinholdt

et al.

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(9), P. 3551 - 3565

Published: April 25, 2024

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 resource-efficient theory, using truncated active-space version multiconfigurational self-consistent field LR ansatz. Therein, investigate eight different formalisms that utilize novel operator transformations allow equations be performed on hardware. Simulating excited state potential energy curves absorption spectra various test cases, identify two promising candidates, dubbed "proj LRSD" "all-proj LRSD".

Language: Английский

Citations

9
Subspace Methods for the Simulation of Molecular Response Properties on a Quantum Computer DOI
Peter Reinholdt, Erik Rosendahl Kjellgren, Juliane Holst Fuglsbjerg

et al.

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(9), P. 3729 - 3740

Published: May 1, 2024

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, LiH, H2O, OH–, NH3, show that unitary coupled cluster outperforms classical projected molecular systems with strong correlation. Finally, formulate damped (complex) response, application nitrogen K-edge X-ray absorption ammonia, C6 coefficients NH3.

Language: Английский

Citations

6
Self-consistent Quantum Linear Response with a Polarizable Embedding Environment DOI
Peter Reinholdt, Erik Rosendahl Kjellgren, Karl Michael Ziems

et al.

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 23, 2025

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 Davidson solver. The latter removes need to construct entire electronic Hessian, improving computational efficiency when going toward larger molecules. introduce new superposition-state-based technique compute Hessian-vector products show that this approach is more resilient noise than our earlier gradient-based approach. demonstrate performance PE-UCCSD model systems such as butadiene para-nitroaniline water find delivers comparable accuracy classical PE-CCSD methods simple closed-shell systems. also explore challenges posed by hardware propose error mitigation techniques maintain accurate results noisy computers.

Language: Английский

Citations

0
Regulation in mechanical properties and structural morphology of M2B-type borides in Fe-B-C alloy DOI
Fengshuo Jin,

Xie Tianjin,

Gao Guihong

et al.

Vacuum, Journal Year: 2025, Volume and Issue: 234, P. 114086 - 114086

Published: Feb. 2, 2025

Language: Английский

Citations

0
Equation-of-motion internally contracted multireference unitary coupled-cluster theory DOI
Shuhang Li, Z. Zhao, Francesco A. Evangelista

et al.

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(15)

Published: April 16, 2025

The accurate computation of excited states remains a challenge in electronic structure theory, especially for systems with ground state that requires multireference treatment. In this work, we introduce novel equation-of-motion (EOM) extension the internally contracted unitary coupled-cluster framework (ic-MRUCC), termed EOM-ic-MRUCC. EOM-ic-MRUCC follows transform-then-diagonalize approach, analogy to its non-unitary counterpart [Datta and Nooijen, J. Chem. Phys. 137, 204107 (2012)]. By employing projective approach optimize state, method retains additive separability proper scaling system size. We show excitation energies are size-intensive if EOM operator satisfies “killer” conditions. Furthermore, propose represent changes reference upon electron via projected many-body operators span active orbitals equations formulated way invariant respect orbital rotations. test truncated single double excitations by computing potential energy curves several BeH2 model system, HF molecule, water undergoing symmetric dissociation. Across these systems, our delivers within 5 mEh (∼0.14 eV) from full configuration interaction. find truncating Baker–Campbell–Hausdorff series fourfold commutators contributes negligible errors (on order 10−5Eh or less), offering practical route highly excited-state calculations reduced computational overhead.

Language: Английский

Citations

0
Reduced Density Matrix Formulation of Quantum Linear Response DOI
Theo Juncker von Buchwald, Karl Michael Ziems, Erik Rosendahl Kjellgren

et al.

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 6, 2024

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 sized molecules much larger basis sets than so far possible. We report qLR results benzene

Language: Английский

Citations

2
Divergences in classical and quantum linear response and equation of motion formulations DOI
Erik Rosendahl Kjellgren, Peter Reinholdt, Karl Michael Ziems

et al.

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(12)

Published: Sept. 25, 2024

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 parameters an idealized noiseless setting. Furthermore, this leads a significant variance when calculations include statistical noise from finite sampling.

Language: Английский

Citations

2
Estimating Molecular Thermal Averages with the Quantum Equation of Motion and Informationally Complete Measurements DOI Creative Commons
Daniele Morrone, N. Walter Talarico, Marco Cattaneo

et al.

Entropy, Journal Year: 2024, Volume and Issue: 26(9), P. 722 - 722

Published: Aug. 23, 2024

By leveraging the Variational Quantum Eigensolver (VQE), "quantum equation of motion" (qEOM) method established itself as a promising tool for quantum chemistry on near-term computers and has been used extensively to estimate molecular excited states. Here, we explore novel application this method, employing it compute thermal averages systems, specifically molecules like ethylene butadiene. A drawback qEOM is that requires measuring expectation values large number observables ground state system, necessary measurements can become bottleneck method. In work, focus through informationally complete positive operator-valued measures (IC-POVMs) achieve reduction in measurement overheads by estimating different interest single set POVMs. We show with numerical simulations combined IC-POVM ensures satisfactory accuracy reconstruction reasonable shots.

Language: Английский

Citations

1
Vibronic Structure of the UV/Visible Absorption Spectra of Phenol and Phenolate: A Hybrid Density Functional Theory─Doktorov’s Quantum Algorithm Approach DOI
R. Hernández, Armand Soldera, Benoı̂t Champagne

et al.

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 24, 2024

The Doktorov's quantum algorithm has been enacted in combination with time-dependent density functional theory (TD-DFT) to simulate the vibronic structure of UV/visible absorption spectra phenol and phenolate molecules. On one hand, DFT TD-DFT are employed classical algorithms calculate ground excited-state electronic structures as well their vibrational frequencies normal modes, whereas, on other for evaluating transition intensities. In comparison a previous study, J. Phys. Chem. A 2024, 128, 4369–4377, which demonstrated proof concept predict ionization spectra, it is applied here medium-size molecules more than 30 without accounting Duschinsky rotations due software limitations. This application also enables assessing impact differences between excited states.

Language: Английский

Citations

0