Variational quantum eigensolver for approximate diagonalization of downfolded Hamiltonians using generalized unitary coupled cluster ansatz
Nicholas P. Bauman, Jaroslav Chládek, Libor Veis, Jiřı́ Pittner, Karol Kowalski
Abstract
Abstract In this paper, we discuss the utilization of variational quantum solver (VQE) and recently introduced generalized unitary coupled cluster (GUCC) formalism for the diagonalization of downfolded/effective Hamiltonians in active spaces. In addition to effective Hamiltonians defined by the downfolding of a subset of virtual orbitals we also consider their form defined by freezing core orbitals, which enables us to deal with larger systems. We also consider various solvers to identify solutions of the GUCC equations. We use N 2 , H 2 O, and C 2 H 4 , as benchmark systems to illustrate the performance of the combined framework.
Topics & Concepts
AnsatzUnitary stateCoupled clusterAtomic orbitalQuantumSolverFormalism (music)Hamiltonian (control theory)Cluster (spacecraft)Quantum mechanicsMathematicsPhysicsMathematical physicsAlgebra over a fieldComputer sciencePure mathematicsMoleculeMathematical optimizationMusicalLawVisual artsArtElectronProgramming languagePolitical scienceQuantum Computing Algorithms and ArchitectureAdvanced Chemical Physics StudiesQuantum many-body systems