%0 Journal Article %J Physical Review Letters %D 2005 %T Fast quantum algorithm for numerical gradient estimation %A Stephen P. Jordan %X Given a blackbox for f, a smooth real scalar function of d real variables, one wants to estimate the gradient of f at a given point with n bits of precision. On a classical computer this requires a minimum of d+1 blackbox queries, whereas on a quantum computer it requires only one query regardless of d. The number of bits of precision to which f must be evaluated matches the classical requirement in the limit of large n. %B Physical Review Letters %V 95 %8 2005/7/28 %G eng %U http://arxiv.org/abs/quant-ph/0405146v2 %N 5 %! Phys. Rev. Lett. %R 10.1103/PhysRevLett.95.050501