17 citations · 92 across the 23 of their papers we have counts for
8 papers · 1 filter
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…
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…
Quantum error mitigation using energy sampling and extrapolation enhanced Clifford data regression
Zhongqi Zhao, Erik Rosendahl Kjellgren, Sonia Coriani +3
Error mitigation is essential for the practical implementation of quantum algorithms on noisy intermediate-scale quantum (NISQ) devices. This work explores and extends Clifford Dat…
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,…
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…
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…
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…