Demonstration of the auxiliary-field Monte Carlo approach for sd-shell nuclei

Abstract

We apply the auxiliary-field Monte Carlo approach to the nuclear shell model in the 1s-0d configuration space. The Hamiltonian was chosen to have isovector pairing and isoscalar multipole-multipole interactions, and the calculations were performed within the fixed-particle, canonical ensemble. The results demonstrate the feasibility of the method for N≠Z even-even and odd-odd N=Z nuclei. In particular, static observables for even-even Ne isotopes and 22Na compare well with results obtained from exact diagonalization of the Hamiltonian. Response functions are presented for 22Ne and compared with exact results, and the viability of cranked calculations for N≠Z even-even nuclei is addressed. We present methods for computing observables in the canonical ensemble using Fourier extraction, and for determining the nucelar shape.