The Schrodinder equation leads to the classical Hamilton-Jacobi equation with an additional term called "quantum potential". This is the start of the Bohmian interpretation of quantum mechanics. The derivation is straigthforward by assuming psi = R exp(iS/hb). The vanishing of the additional term for the classical limit hb->0 illustrates nicely the link between QM and CM. I would like to know if a similar find could be done for a system of interacting spins (or qbits !). I take interacting spins as an example of 'discrete system' (no space coordinate). Is there also an Hamilton-Jacobi to be derived ? If yes, is there also a classical limit to be seen ? I would be interrested in ideas, suggestions and eventually references related to this topic.