Coherent state wave function for systems with spin-dependent correlations

We propose a variational wave function which uses coherent states to represent the spin state of particles, and describes systems with spin-dependent correlations. Spin states are parametrized by a continuous variable that looks like a classical spin vector. Correlation operators are represented as simple integrals, without commutator terms, which can be evaluated using standard or Monte Carlo techniques. Explicit calculations on liquid ³He using our wave function give good agreement with standard methods. Applications to systems in condensed matter and nuclear physics are discussed.