QUANTUM MONTE CARLO CALCULATIONS FOR NUCLEI ANDNUCLEAR MATTER

摘要

We report on the most recent applications of the Auxiliary Field Diffusion Monte Carlo(AFDMC) method from light nuclei to nuclear matter. Recent calculations of the groundstate energy of ~4He, ~8He, ~(16)O, ~(40)Ca and symmetric nuclear matter using the semi-realisttwo-body interaction, Argonne v'_6,which includes tensor and tensor-r forces, are pre-sented and discussed. Comparison of the light nuclei results to those of Green's functionMonte Carlo calculations shows the high level of accuracy of AFDMC for both open andclosed shell nuclei, particularly when used in conjunction with the fixed phase constraint(FP–AFDMC). The application to heavier nuclei and to nuclear matter demonstratesthe FP–AFDMC uniqueness, amongst the Quantum Monte Carlo methods, in dealingwith large nucleonic systems interacting via realistic nuclear potentials and with un-precedented accuracy. Discrepancies have been found with previous Fermi Hyper NettedChain and Brueckner–Hartree–Fock calculations. Most interestingly, the nuclear mattercalculations strongly indicate that many-body forces are very important even at experi-mental equilibrium density. Preliminary results for pure neutron matter in both normaland BCS phase with Argonne v_8'plus Urbana IX three-nucleon interaction are alsopresented.