8 papers · 1 filter
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…
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…
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…
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…
Understanding and mitigating noise in molecular quantum linear response for spectroscopic properties on quantum computers
Karl Michael Ziems, Erik Rosendahl Kjellgren, Stephan P. A. Sauer +2
The promise of quantum computing to circumvent the exponential scaling of quantum chemistry has sparked a race to develop chemistry algorithms for quantum architecture. However, mo…
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…