Theory of Computing ------------------- Title : Discrete-Query Quantum Algorithm for NAND Trees Authors : Andrew M. Childs, Richard Cleve, Stephen P. Jordan, and David Yonge-Mallo Volume : 5 Number : 5 Pages : 119-123 URL : https://theoryofcomputing.org/articles/v005a005 Abstract -------- This is a comment on the article "A Quantum Algorithm for the Hamiltonian NAND Tree" by Edward Farhi, Jeffrey Goldstone, and Sam Gutmann, Theory of Computing 4 (2008) 169-190. That paper gave a quantum algorithm for evaluating NAND trees with running time O(sqrt{N}) in the Hamiltonian query model. In this note, we point out that their algorithm can be converted into an algorithm using N^{1/2 + o(1)} queries in the conventional (discrete) quantum query model.