  We experimentally demonstrate the noiseless teleportation of a single photon
by conditioning on quadrature Bell measurement results near the origin in phase
space and thereby circumventing the photon loss that otherwise occurs even in
optimal gain-tuned continuous-variable quantum teleportation. In general,
thanks to this loss suppression, the noiseless conditional teleportation can
preserve the negativity of the Wigner function for an arbitrary pure input
state and an arbitrary pure entangled resource state. In our experiment, the
positive value of the Wigner function at the origin for the unconditional
output state, W(0,0) = 0.015 $\pm$ 0.001, becomes clearly negative after
conditioning, W(0,0) = $-$0.025 $\pm$ 0.005, illustrating the advantage of
noiseless conditional teleportation.
