Quantum Monte Carlo study of inhomogeneous neutron matter

We present an ab-initio study of neutron drops. We use Quantum Monte Carlo techniques to calculate the energy up to 54 neutrons in different external potentials, and we compare the results with Skyrme forces. We also calculate the rms radii and radial densities, and we find that a re-adjustment of the gradient term in Skyrme is needed in order to reproduce the properties of these systems given by the ab-initio calculation. By using the ab-initio results for neutron drops for close- and open-shell configurations, we suggest how to improve Skyrme forces when dealing with systems with large isospin-asymmetries like neutron-rich nuclei.Comment: 8 pages, 6 figures, talk given at Horizons on Innovative Theories, Experiments, and Supercomputing in Nuclear Physics 2012, (HITES2012), New Orleans, Louisiana, June 4-7, 2012; to appear in Journal of Physics: Conference Series (JPCS

Auxiliary Field Diffusion Monte Carlo calculation of nuclei with A<40 with tensor interactions

We calculate the ground-state energy of 4He, 8He, 16O, and 40Ca using the auxiliary field diffusion Monte Carlo method in the fixed phase approximation and the Argonne v6' interaction which includes a tensor force. Comparison of our light nuclei results to those of Green's function Monte Carlo calculations shows the accuracy of our method for both open and closed shell nuclei. We also apply it to 16O and 40Ca to show that quantum Monte Carlo methods are now applicable to larger nuclei.Comment: 4 pages, no figure

Quantum Monte Carlo calculations of symmetric nuclear matter

We present an accurate numerical study of the equation of state of nuclear matter based on realistic nucleon--nucleon interactions by means of Auxiliary Field Diffusion Monte Carlo (AFDMC) calculations. The AFDMC method samples the spin and isospin degrees of freedom allowing for quantum simulations of large nucleonic systems and can provide quantitative understanding of problems in nuclear structure and astrophysics.Comment: Final version published in the Phys. Rev. Let

Contact interaction in an unitary ultracold Fermi gas

An ultracold Fermi atomic gas at unitarity presents universal properties that in the diluted limit can be well described by a contact interaction. By employing a guide function with correct boundary conditions and making simple modifications to the sampling procedure we are able to handle for the first time a true contact interaction in a quantum Monte Carlo calculation. The results are obtained with small variances. Our calculations for the Bertsch and contact parameters are in excellent agreement with published experiments. The possibility of using a more faithfully description of ultracold atomic gases can help uncover features yet unknown of the ultracold atomic gases. In addition, this work paves the way to perform quantum Monte Carlo calculations for systems interacting with contact interactions, where in many cases the description using potentials with finite effective range might not be accurate