1,527 research outputs found
Chiral Expansion, Renormalization and the Nuclear Force
The renormalization of singular chiral potentials as applied to NN scattering
and the structure of the deuteron is discussed. It is shown how zero range
theories may be implemented non-perturbatively as constrained from known long
range NN forces.Comment: Talk at International IUPAP Conference on Few-Body Problems in
Physics (FB18), Santos-Sao Paulo (Brasil), 21-26 August 200
Deuteron radial moments for renormalized chiral potentials
We calculate deuteron positive and negative radial moments involving any
bilinear function of the deuteron S and D wave functions for renormalized OPE
and TPE chiral potentials. The role played by the strong singularities of the
potentials at the origin and the short distance insensitivity of the results
when the potentials are fully iterated is emphasized as compared to realistic
potentials.Comment: 3 pages, 2 figures. Poster presented at 4th International Conference
on Quarks and Nuclear Physics (QNP06), Madrid, Spain, 5-10 Jun 200
Renormalization Group Analysis of Boundary Conditions in Potential Scattering
We analyze how a short distance boundary condition for the Schrodinger
equation must change as a function of the boundary radius by imposing the
physical requirement of phase shift independence on the boundary condition. The
resulting equation can be interpreted as a variable phase equation of a
complementary boundary value problem. We discuss the corresponding infrared
fixed points and the perturbative expansion around them generating a short
distance modified effective range theory. We also discuss ultraviolet fixed
points, limit cycles and attractors with a given fractality which take place
for singular attractive potentials at the origin. The scaling behaviour of
scattering observables can analytically be determined and is studied with some
emphasis on the low energy nucleon-nucleon interaction via singular pion
exchange potentials. The generalization to coupled channels is also studied.Comment: 31 pages, 8 figure
Gauge invariance in the presence of a cutoff
We use the method of gauging equations to construct the electromagnetic
current operator for the two-nucleon system in a theory with a finite cutoff.
The employed formulation ensures that the two-nucleon T-matrix and
corresponding five-point function, in the cutoff theory, are identical to the
ones formally defined by a reference theory without a cutoff. A feature of our
approach is that it effectively introduces a cutoff into the reference theory
in a way that maintains the long-range part of the exchange current operator;
for applications to effective field theory (EFT), this property is usually
sufficient to guarantee the predictive power of the resulting cutoff theory. In
addition, our approach leads to Ward-Takahashi (WT) identities that are linear
in the interactions.
From the point of view of EFT's where such a WT identity is satisfied in the
reference theory, this ensures that gauge invariance in the cutoff theory is
maintained order by order in the expansion.Comment: 15 pages, 2 figure
Kohn-Sham calculations combined with an average pair-density functional theory
A recently developed formalism in which Kohn-Sham calculations are combined
with an ``average pair density functional theory'' is reviewed, and some new
properties of the effective electron-electron interaction entering in this
formalism are derived. A preliminary construction of a fully self-consitent
scheme is also presented in this framework.Comment: submitted to Int. J. Mod. Phys. B (proceedings of the 30th
International Workshop on Condensed Matter Theories
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