Maximally local two-nucleon interactions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mn>3</mml:mn></mml:msup><mml:mi mathvariant="normal">LO</mml:mi></mml:mrow></mml:math> in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="normal">Δ</mml:mi></mml:math>-less chiral effective field theory
Rahul Somasundaram, J. E. Lynn, L. Huth, A. Schwenk, Ingo Tews
Abstract
We present new maximally local two-nucleon interactions derived in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi mathvariant="normal">Δ</a:mi></a:math>-less chiral effective field theory up to next-to-next-to-next-to-leading order (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:msup><c:mrow><c:mi mathvariant="normal">N</c:mi></c:mrow><c:mn>3</c:mn></c:msup><c:mi>LO</c:mi></c:mrow></c:math>), which include all contact and pion-exchange contributions to the nuclear Hamiltonian up to this order. Our interactions are fit to nucleon-nucleon phase shifts using a Bayesian statistical approach, and explore a wide cutoff range from <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:mn>0.6</e:mn><e:mo>–</e:mo><e:mn>0.9</e:mn></e:mrow></e:math> fm (<f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mo>≈</f:mo><f:mn>660</f:mn><f:mo>–</f:mo><f:mn>440</f:mn><f:mspace width="4pt"/><f:mi>MeV</f:mi></f:mrow></f:math>). These interactions can be straightforwardly employed in quantum Monte Carlo methods, such as the auxiliary field diffusion Monte Carlo method. Together with local three-nucleon forces, calculations with these new interactions will provide improved benchmarks for the structure of atomic nuclei and serve as crucial input to analyses of astrophysical phenomena of neutron stars, such as binary neutron-star mergers. Published by the American Physical Society 2024