  Phase-space representations based on coherent states (P, Q, Wigner) have been
successful in the creation of stochastic differential equations (SDEs) for the
efficient stochastic simulation of high dimensional quantum systems. However
many problems using these techniques remain intractable over long integrations
times. We present a number-phase Wigner representation that can be unraveled
into SDEs. We demonstrate convergence to the correct solution for an anharmonic
oscillator with small dampening for significantly longer than other phase space
representations. This process requires an effective sampling of a non-classical
probability distribution. We describe and demonstrate a method of achieving
this sampling using stochastic weights.
