Atomic Transition Rates on a Quantum Annealer

Abstract

Electric-dipole (E1) transition rates underlie applications across many areas of physics and demand more accurate wavefunctions than ground-state energies do. We report the first calculation of E1 transition rates on a D-Wave quantum annealer, for neutral Li, Li-like Be, neutral Na, and Na-like Mg. We use a zooming-and-sigma-annealing scheme with floating-point encoding within the Quantum Annealer Eigensolver (QAE) algorithm, which yields ground-state eigenvectors accurate to the chosen three decimal places. Treating the lowest even-parity (${}^2{S}_{1/2}$) and odd-parity (${}^2{P}_{1/2}$, ${}^2{P}_{3/2}$) states as separate angular-symmetry sectors gives QAE access to excited atomic configurations for transition-rate calculations. Our results reproduce relativistic configuration-interaction values obtained classically to within numerical precision, demonstrating that the QAE framework extends to a broader class of atomic properties on near-term quantum hardware.