Improved trial wave functions with 4-body correlations for Nuclear Quantum Monte Carlo

Quantum Monte Carlo techniques are used to study various aspects of nuclear physics with great accuracy. A major difficulty with these methods is coming up with an accurate and tractable trial wave function. Until now Auxiliary Field Diffusion Monte Carlo calculations have been done with up to 2-body correlations in the trial wave function. We have extended this to include up to 4-body correlations using two slightly different expansions. Using these new wave functions we have done binding energy calculations for $^{4}$He, $^{16}$O, $^{40}$Ca, and symmetric nuclear matter at saturation density. For each calculation the energy decreased with respect to calculations with 2-body correlations. We also discuss applications of these new wave functions to physical systems such as particle clustering in neutron star crusts.