63 citations · 138 across the 19 of their papers we have counts for
10 papers · 1 filter
Orbital-optimized spin-adapted multistate contracted VQE for excited states and properties on quantum hardware
Erik Rosendahl Kjellgren, Karl Michael Ziems, Peter Reinholdt +3
We introduce the orbital-optimized multistate contracted variational quantum eigensolver (oo-MC-VQE) method with spin-adapted operators for the computation of ground and excited st…
State-Averaged Quantum Algorithms for Multiconfigurational Surface Chemistry: A Benchmark on Rh@TiO2(110)
Ernst Dennis Lægteskov Binau Larsson, Erik Kjellgren, Peter Reinholdt +1
Accurate modeling of surface catalytic processes often requires methods capable of describing strong correlation, charge transfer, and multiple closely lying electronic states. Whi…
Cost-effective scalable quantum error mitigation for tiled Ansätze
Oskar Graulund Lentz Rasmussen, Erik Kjellgren, Peter Reinholdt +4
We introduce a cost-effective quantum error mitigation technique that builds upon the recent Ansatz-based gate and readout error mitigation method (M0). The technique, tiled M0, le…
Exact closed-form expression for unitary spin-adapted fermionic singlet double excitation operators
Erik Rosendahl Kjellgren, Karl Michael Ziems, Peter Reinholdt +3
We derive exact closed-form expressions for the matrix exponential of the anti-Hermitian spin-adapted singlet double excitation fermionic operators. These expressions enable the ef…
Hyperfine Coupling Constants on Quantum Computers: Performance, Errors, and Future Prospects
Phillip W. K. Jensen, Gustav Stausbøll Hedemark, Karl Michael Ziems +6
We present the first implementation and computation of electron spin resonance isotropic hyperfine coupling constants (HFCs) on quantum hardware. As illustrative test cases, we com…
Divergences in classical and quantum linear response and equation of motion formulations
Erik Rosendahl Kjellgren, Peter Reinholdt, Karl Michael Ziems +3
Calculating molecular properties using quantum devices can be done through the quantum linear response (qLR) or, equivalently, the quantum equation of motion (qEOM) formulations. D…
Electric Field Gradient Calculations for Ice VIII and IX using Polarizable Embedding: A Comparative Study on Classical Computers and Quantum Simulators
Dániel Nagy, Peter Reinholdt, Phillip W. K. Jensen +7
We test the performance of the Polarizable Embedding Variational Quantum Eigensolver Self-Consistent-Field (PE-VQE-SCF) model for computing electric field gradients with comparison…
Which options exist for NISQ-friendly linear response formulations?
Karl Michael Ziems, Erik Rosendahl Kjellgren, Peter Reinholdt +4
Linear response (LR) theory is a powerful tool in classic quantum chemistry crucial to understanding photo-induced processes in chemistry and biology. However, performing simulatio…
Quantum Equation of Motion with Orbital Optimization for Computing Molecular Properties in Near-Term Quantum Computing
Phillip W. K. Jensen, Erik Rosendahl Kjellgren, Peter Reinholdt +4
Determining the properties of molecules and materials is one of the premier applications of quantum computing. A major question in the field is how to use imperfect near-term quant…
The variational quantum eigensolver self-consistent field method within a polarizable embedded framework
Erik Rosendahl Kjellgren, Peter Reinholdt, Aaron Fitzpatrick +6
We formulate and implement the Variational Quantum Eigensolver Self Consistent Field (VQE-SCF) algorithm in combination with polarizable embedding (PE), thereby extending PE to the…