Abstract. We present recent results for 4 He and 6 Li obtained with improved NN interactions derived from chiral effective field theory up to N 4 LO. The many-body calculations are performed order-by-order in the chiral expansion. At N 3 LO and N 4 LO additional renormalization using the Similarity Renormalization Group is adopted to improve numerical convergence of the many-body calculations. We discuss results for the ground state energies, as well as the magnetic moment and the low-lying spectrum of 6 Li.
Nuclear potential from chiral EFTChiral effective field theory (EFT) allows one to derive nuclear forces (and corresponding electoweak currents) in a systematical way [1]. In particular, the leading order (LO) and next-to-leading order (NLO) contributions to the interaction are given solely by nucleon-nucleon (NN) operators while three-nucleon forces (3NFs) appear first at next-to-next-to-leading order (N 2 LO) [2] in the chiral expansion. Four-nucleon forces are even more suppressed and start contributing at N 3 LO. The chiral power counting thus provides a natural explanation of the observed hierarchy of nuclear forces.In Refs. [3, 4] a new generation of chiral EFT NN potentials up to N 4 LO was developed, using local regulators for the long-range terms and with reduced finite-cutoff artefacts by employing a novel ultraviolet regularization scheme; in addition, a procedure to estimate the theoretical uncertainties due to the truncation of the chiral expansion was proposed (see also [5]). Here we present results for 4 He and 6 Li obtained with these improved chiral NN potentials using a regulator of R = 1.0 fm [6]. a