The Canonical Nuclear Many-Body Problem as an Effective Theory

Recently it was argued that it might be possible treat the conventional nuclear structure problem -- nonrelativistic point nucleons interacting through a static and rather singular potential -- as an effective theory in a shell-model basis. In the first half of this talk we describe how such a program can be carried out for the simplest nuclei, the deuteron and 3He, exploiting a new numerical technique for solving the self-consistent Bloch-Horowitz equation. Some of the properties of proper effective theories are thus illustrated and contrasted with the shell model. In the second half of the talk we use these examples to return to a problem that frustrated the field three decades ago, the possibility of reducing the effective interactions problem to perturbation theory. We show, by exploiting the Talmi integral expansion, that hard-core potentials can be systematically softened by the introduction of a series of contact operators familiar from effective field theory. The coefficients of these operators can be run analytically by a renormalization group method in a scheme-independent way, with the introduction of suitable counterterms. Once these coefficients are run to the shell model scale, we show that the renormalized coefficients contain all of the information needed to evaluate perturbative insertions of the remaining soft potential. The resulting perturbative expansion is shown to converge in lowest order for the simplest nucleus, the deuteron.Comment: Latex, 12 pages, 2 figures Talk presented at the International Symposium on Nuclei and Nucleons, held in honor of Achim Richter Typos corrected in this replacemen

Voronoi Particle Merging Algorithm for PIC Codes

We present a new particle-merging algorithm for the particle-in-cell method. Based on the concept of the Voronoi diagram, the algorithm partitions the phase space into smaller subsets, which consist of only particles that are in close proximity in the phase space to each other. We show the performance of our algorithm in the case of the two-stream instability and the magnetic shower.Comment: 11 figure

Optical processing for landmark identification

A study of optical pattern recognition techniques, available components and airborne optical systems for use in landmark identification was conducted. A data base of imagery exhibiting multisensor, seasonal, snow and fog cover, exposure, and other differences was assembled. These were successfully processed in a scaling optical correlator using weighted matched spatial filter synthesis. Distinctive data classes were defined and a description of the data (with considerable input information and content information) emerged from this study. It has considerable merit with regard to the preprocessing needed and the image difference categories advanced. A optical pattern recognition airborne applications was developed, assembled and demontrated. It employed a laser diode light source and holographic optical elements in a new lensless matched spatial filter architecture with greatly reduced size and weight, as well as component positioning toleranced

Three-fermion problems in optical lattices

We present exact results for the spectra of three fermionic atoms in a single well of an optical lattice. For the three lowest hyperfine states of Li6 atoms, we find a Borromean state across the region of the distinct pairwise Feshbach resonances. For K40 atoms, nearby Feshbach resonances are known for two of the pairs, and a bound three-body state develops towards the positive scattering-length side. In addition, we study the sensitivity of our results to atomic details. The predicted few-body phenomena can be realized in optical lattices in the limit of low tunneling.Comment: 4 pages, 4 figures, minor changes, to appear in Phys. Rev. Let

Beyond-the-Standard-Model matrix elements with the gradient flow

At the Forschungszentrum Juelich (FZJ) we have started a long-term program that aims to determine beyond-the-Standard-Model (BSM) matrix elements using the gradient flow, and to understand the impact of BSM physics in nucleon and nuclear observables. Using the gradient flow, we propose to calculate the QCD component of key beyond the Standard Model (BSM) matrix elements related to quark and strong theta CP violation and the strange content within the nucleon. The former set of matrix elements impacts our understanding of Electric Dipole Moments (EDMs) of nucleons and nuclei (a key signature of BSM physics), while the latter contributes to elastic recoil of Dark Matter particles off nucleons and nuclei. If successful, these results will lay the foundation for extraction of BSM observables from future low-energy, high-intensity and high-accuracy experimental measurements.Comment: 7 pages, 2 figures, presented at the 32nd International Symposium on Lattice Field Theory (Lattice 2014). Correct version of proceedings. Different wording of few paragraphs and different notation on few formulas. Added 1 referenc