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20232026
most citedWhich options exist for NISQ-friendly linear response formulations?

17 citations · 91 across the 22 of their papers we have counts for

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physics.chem-ph2026

Analytical Nuclear Gradients and Hessians on Quantum Hardware via Orbital-Optimized VQE with Error Mitigation

Renato Olarte Hernandez, Karl Michael Ziems, Erik Kjellgren +3

Nuclear gradients and Hessians are fundamental quantities in computational chemistry, essential for a wide range of applications including geometry optimization, vibrational spectr…

physics.chem-ph2026

Perturbatively Corrected Linear Response Selected Configuration Interaction

Peter Reinholdt, Erik Kjellgren, Jacob Kongsted

Selected configuration interaction (SCI) methods have emerged as powerful, lower-cost alternatives to full configuration interaction (FCI) for ground- and excited-state energies. S…

physics.chem-ph2025

Orbital-Optimized Unitary Coupled Cluster for Indirect Nuclear Spin-Spin Coupling Constants within a Quantum Linear Response Framework

Juliane H. Fuglsbjerg, Peter Reinholdt, Erik Kjellgren +4

We present a quantum linear response (qLR) approach within an active-space framework for computing indirect nuclear spin-spin coupling constants, a key ingredient in NMR spectra pr…

physics.chem-ph2025

Linear Response Selected Configuration Interaction

Peter Reinholdt, Erik Kjellgren, Jacob Kongsted

In this work, we extend selected configuration interaction (SCI) methods beyond energies and expectation values by introducing a linear response (LR) framework for molecular respon…

physics.chem-ph2025

Reduced density matrix and cumulant approximations of quantum linear response

Theo Juncker von Buchwald, Erik Rosendahl Kjellgren, Jacob Kongsted +3

Linear response (LR) is an important tool in the computational chemist's toolbox. It is therefore no surprise that the emergence of quantum computers has led to a quantum version,…

physics.chem-ph2025

Redundant parameter dependencies in truncated classic and quantum Linear Response and Equation of Motion theory

Erik Rosendahl Kjellgren, Peter Reinholdt, Karl Michael Ziems +3

Extracting molecular properties from a wave function can be done through the linear response (LR) formalism or, equivalently, the equation of motion (EOM) formalism. For a simple m…

physics.chem-ph2025★ 5 cited

Critical Limitations in Quantum-Selected Configuration Interaction Methods

Peter Reinholdt, Karl Michael Ziems, Erik Rosendahl Kjellgren +3

Quantum Selected Configuration Interaction (QSCI) methods (also known as Sample-based Quantum Diagonalization, SQD) have emerged as promising near-term approaches to solving the el…

physics.chem-ph2024★ 4 cited

Self-consistent Quantum Linear Response with a Polarizable Embedding environment

Peter Reinholdt, Erik Rosendahl Kjellgren, Karl Michael Ziems +3

Quantum computing presents a promising avenue for solving complex problems, particularly in quantum chemistry, where it could accelerate the computation of molecular properties and…

physics.chem-ph2024★ 9 cited

Reduced density matrix formulation of quantum linear response

Theo Juncker von Buchwald, Karl Michael Ziems, Erik Rosendahl Kjellgren +3

The prediction of spectral properties via linear response (LR) theory is an important tool in quantum chemistry for understanding photo-induced processes in molecular systems. With…

physics.chem-ph2024★ 14 cited

Subspace methods for the simulation of molecular response properties on a quantum computer

Peter Reinholdt, Erik Rosendahl Kjellgren, Juliane Holst Fuglsbjerg +4

We explore Davidson methods for obtaining excitation energies and other linear response properties within quantum self-consistent linear response (q-sc-LR) theory. Davidson-type me…