  This letter is a proof of concept for quantum power flow (QPF) algorithms
which underpin various unprecedentedly efficient power system analytics
exploiting quantum computing. Our contributions are three-fold: 1) Establish a
quantum-state-based fast decoupled model empowered by Hermitian and constant
Jacobian matrices; 2) Devise an enhanced Harrow-Hassidim-Lloyd (HHL) algorithm
to solve the fast decoupled QPF; 3) Further improve the HHL efficiency by
parameterizing quantum phase estimation and reciprocal rotation only at the
beginning stage. Promising test results validate the accuracy and efficacy of
QPF and demonstrate QPF's enormous potential in the era of quantum computing.
