Effective interactions from q-deformed inspired transformations

From the mass term for the transformed quark fields, we obtain effective contact interactions of the NJL type. The parameters of the model that maps a system of non-interacting transformed fields into quarks interacting via NJL contact terms are discussed

Fixed points of the Similarity Renormalization Group and the Nuclear Many-Body Problem

The Similarity Renormalization Group reduces the off-shellness by driving the evolved interaction towards a diagonal band. We analyze the infrared limit and the corresponding on-shell interactions and its consequences for light nuclei. Using a harmonic oscillator shell model we obtain a Tjon line B(4He)= 4B(3H)-3B(2H) which can be understood from a combinatorics counting of nucleon pairs and triplets in the triton and alpha-particle and compares favorably with realistic calculations.Comment: Presented by E.R.A. at the 22th European Conference On Few-Body Problems In Physics: EFB22 9 - 13 Sep 2013, Krakow (Poland), 5 pages, 3 figures (corrections and references added

Renormalization group invariance in pionless effective field theory for the NN system

We consider the NN interaction in pionless effective field theory (EFT) up to next-to-next-to-leading order (NNLO) and use a recursive subtractive renormalization scheme to describe NN scattering in the 1S0 channel. We fix the strengths of the contact interactions at a reference scale, chosen to be the one that provides the best fit for the phase-shifts, and then slide the renormalization scale by evolving the driving terms of the subtracted Lippmann-Schwinger equation through a non-relativistic Callan-Symanzik equation. The results show that such a systematic renormalization scheme with multiple subtractions is fully renormalization group invariant.Comment: Talk given at The 21st European Conference on Few-Body Problems in Physics, Salamanca, Spain, August 29th - September 3rd, 201

Similarity renormalization group evolution of NNNN interactions within a subtractive renormalization scheme

We apply the similarity renormalization group (SRG) approach to evolve a nucleon-nucleon ($NN$) interaction in leading-order (LO) chiral effective field theory (ChEFT), renormalized within the framework of the subtracted kernel method (SKM). We derive a fixed-point interaction and show the renormalization group (RG) invariance in the SKM approach. We also compare the evolution of $NN$ potentials with the subtraction scale through a SKM RG equation in the form of a non-relativistic Callan-Symanzik (NRCS) equation and the evolution with the similarity cutoff through the SRG transformation.Comment: Talk given at 19th International IUPAP Conference on Few-Body Problems in Physics (FB19), Bonn, Germany, August 31st - September 5th, 200

Similarity Renormalization Group Evolution of Chiral Effective Nucleon-Nucleon Potentials in the Subtracted Kernel Method Approach

Methods based on Wilson's renormalization group have been successfully applied in the context of nuclear physics to analyze the scale dependence of effective nucleon-nucleon ($NN$) potentials, as well as to consistently integrate out the high-momentum components of phenomenological high-precision $NN$ potentials in order to derive phase-shift equivalent softer forms, the so called $V_{low-k}$ potentials. An alternative renormalization group approach that has been applied in this context is the Similarity Renormalization Group (SRG), which is based on a series of continuous unitary transformations that evolve hamiltonians with a cutoff on energy differences. In this work we study the SRG evolution of a leading order (LO) chiral effective $NN$ potential in the $^1 S_0$ channel derived within the framework of the Subtracted Kernel Method (SKM), a renormalization scheme based on a subtracted scattering equation.Comment: Published versio

The Coester Line in Relativistic Mean Field Nuclear Matter

The Walecka model contains essentially two parameters that are associated with the Lorentz scalar (S) and vector (V) interactions. These parameters are related to a two-body interaction consisting of S and V, imposing the condition that the two-body binding energy is fixed. We have obtained a set of different values for the nuclear matter binding energies at equilibrium densities. We investigated the existence of a linear correlation between $B_N$ and $\rho_0$, claimed to be universal for nonrelativistic systems and usually known as the Coester line, and found an approximate linear correlation only if $V?S$ remains constant. It is shown that the relativistic content of the model, which is related to the strength of $V?S$, is responsible for the shift of the Coester line to the empirical region of nuclear matter saturation.Comment: 7 pages, 5 figure