



00981nas a2200133   4500008004100000245005900041210005900100260001300159490000800172520059000180100002400770700001600794856003700810       2011                        eng d00aDirect Fidelity Estimation from Few Pauli Measurements0 aDirect Fidelity Estimation from Few Pauli Measurements  c2011/6/80 v1063 a  We describe a simple method for certifying that an experimental device
prepares a desired quantum state rho. Our method is applicable to any pure
state rho, and it provides an estimate of the fidelity between rho and the
actual (arbitrary) state in the lab, up to a constant additive error. The
method requires measuring only a constant number of Pauli expectation values,
selected at random according to an importance-weighting rule. Our method is
faster than full tomography by a factor of d, the dimension of the state space,
and extends easily and naturally to quantum channels.
1 aFlammia, Steven, T.1 aLiu, Yi-Kai  uhttp://arxiv.org/abs/1104.4695v3