Reduced Dipole Element in Barium Develops Quantum Metrology

Researchers at Quantum Technologies, National University of Singapore have achieved a high-precision measurement of the reduced electric-dipole matrix element in barium+. By comparing off-resonant scattering rates with dispersive Stark-shift measurements, the team determined the static dipole matrix element, corresponding to an excited-state radiative lifetime of nanoseconds. This determination directly improves the evaluation of blackbody radiation (BBR) shift, a major source of error in room-temperature optical clock error budgets. The work also establishes a stringent benchmark for atomic-structure calculations and advances applications in quantum metrology and fundamental physics…