Color Superconductivity and Radius of Quark Star in Extended NJL Model by Using the Dimensional Regularization

A radius of a dense star on the color superconducting phase is investigated in an extended NJL type model with two flavors of quarks. Since the model is non-renormalizable, the results depend on the regularization procedure. Here we apply the dimensional regularization and evaluate the radius of a dense star. Evaluating the TOV equation, we show the relationship between mass and radius of the dense star in the dimensional regularization.Comment: 4 pages.To appear in the proceedings of 7th Workshop on Quantum Field Theory Under the Influence of External Conditions (QFEXT 05), Barcelona, Catalonia, Spain, 5-9 Sep 2005. References are ad

Radiative Symmetry Breaking and Dynamical Origin of Cosmological Constant in ϕ4\phi^4 Theory with Non-Linear Curvature Coupling

A scalar self-interacting theory non-linearly coupled with some power of the curvature have a possibility to explain the current smallness of the cosmological constant. Here one concentrate on a massless scalar field in the four-dimensional Fridmann-Robertson-Walker (FRW) spacetime with flat spatial part. One show the phase structure of radiative symmetry breaking and review a dynamical resolution of the cosmological constant problem.Comment: 9 pages. To appear in the proceedings of 7th Workshop on Quantum Field Theory Under the Influence of External Conditions (QFEXT 05), Barcelona, Catalonia, Spain, 5-9 Sep 200

Supersymmetric Nambu-Jona-Lasinio Model in an External Gravitational Field

We investigate the effect of an external gravitational fields to the chiral symmetry breaking in the SUSY (supersymmetric) NJL (Nambu-Jona-Lasinio) model non-minimally interacting with external supergravity. Evaluating the effective potential in the leading order of the $1/N_{c}$-expansion and in the linear curvature approximation it is found the possibility of the chiral symmetry breaking in the SUSY NJL model in an external gravitational fields. In the broken phase the dynamically generated mass is analytically and numerically calculated.Comment: 8 pages, Latex, epic.sty and eepic.sty are use

Phase diagram of Nambu-Jona-Lasinio model with dimensional regularization

We investigate the phase diagram on temperature-chemical potential plane in the Nambu-Jona-Lasinio model with the dimensional regularization. While the structure of the resulting diagram shows resemblance to the one in the frequently used cutoff regularization, some results of our study indicate striking difference between these regularizations. The diagram in the dimensional regularization exhibits strong tendency of the first order phase transition.Comment: 9 pages, 9 figure

Schwinger-Dyson Analysis of Dynamical Symmetry Breaking on a Brane with Bulk Yang-Mills Theory

The dynamically generated fermion mass is investigated in the flat brane world with (4+delta)-dimensional bulk space-time, and in the Randall-Sundrum (RS) brane world. We consider the bulk Yang-Mills theory interacting with the fermion confined on a four-dimensional brane. Based on the effective theory below the reduced cutoff scale on the brane, we formulate the Schwinger-Dyson equation of the brane fermion propagator. By using the improved ladder approximation we numerically solve the Schwinger-Dyson equation and find that the dynamical fermion mass is near the reduced cutoff scale on the brane for the flat brane world with delta >= 3 and for the RS brane world. In RS brane world KK excited modes of the bulk gauge field localized around the y = pi R brane and it enhances the dynamical symmetry breaking on the brane. The decay constant of the fermion and the anti-fermion composite operator can be taken to be the order of the electroweak scale much smaller than the Planck scale. Therefore electroweak mass scale can be realized from only the Planck scale in the RS brane world due to the fermion and the anti-fermion pair condensation. That is a dynamical realization of Randall-Sundrum model which solves the weak-Planck hierarchy problem.Comment: 21 pages, 12 figures; typos corrected, references added and updated, footnotes adde

Superconducting Fluctuations in a Multi-Band 1D Hubbard Model

A renormalization-group and bosonization approach for a multi-band Hubbard Hamiltonian in one dimension is described. Based on the limit of many bands, it is argued that this Hamiltonian with bare repulsive electron-electron interactions is scaled under specific conditions to a model in which superconducting fluctuations dominate.Comment: 12 pages + 1 fig, Revtex, Preprint - Los Alamo

The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells

Adenosine modulates a wide variety of biological processes via adenosine receptors. In the exocrine pancreas, adenosine regulates transepithelial anion secretion in duct cells and is considered to play a role in acini-to-duct signaling. To identify the functional adenosine receptors and Cl− channels important for anion secretion, we herein performed experiments on Capan-1, a human pancreatic duct cell line, using open-circuit Ussing chamber and gramicidin-perforated patch-clamp techniques. The luminal addition of adenosine increased the negative transepithelial potential difference (V te) in Capan-1 monolayers with a half-maximal effective concentration value of approximately 10 μM, which corresponded to the value obtained on whole-cell Cl− currents in Capan-1 single cells. The effects of adenosine on V te, an equivalent short-circuit current (I sc), and whole-cell Cl− currents were inhibited by CFTRinh-172, a cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel inhibitor. The adenosine A2B receptor agonist, BAY 60-6583, increased I sc and whole-cell Cl− currents through CFTR Cl− channels, whereas the A2A receptor agonist, CGS 21680, had negligible effects. The A2B receptor antagonist, PSB 603, inhibited the response of I sc to adenosine. Immunohistochemical analysis showed that the A2A and A2B receptors colocalized with Ezrin in the luminal membranes of Capan-1 monolayers and in rat pancreatic ducts. Adenosine elicited the whole-cell Cl− currents in guinea pig duct cells. These results demonstrate that luminal adenosine regulates anion secretion by activating CFTR Cl− channels via adenosine A2B receptors on the luminal membranes of Capan-1 cells. The present study endorses that purinergic signaling is important in the regulation of pancreatic secretion

Dynamical symmetry breaking in the external gravitational and constant magnetic fields

We investigate the effects of the external gravitational and constant magnetic fields to the dynamical symmetrybreaking. As simple models of the dynamical symmetry breaking we consider the Nambu-Jona-Lasinio (NJL) model and the supersymmetric Nambu-Jona-Lasinio (SUSY NJL) model non-minimally interacting with the external gravitational field and minimally interacting with constant magnetic field. The explicit expressions for the scalar and spinor Green functions are found up to the linear terms on the spacetime curvature and exactly for a constant magnetic field. We obtain the effective potential of the above models from the Green functions in the magnetic field in curved spacetime. Calculating the effective potential numerically with the varying curvature and/or magnetic fields we show the effects of the external gravitational and magnetic fields to the phase structure of the theories. In particular, increase of the curvature in the spontaneously broken chiral symmetry phase due to the fixed magnetic field makes this phase to be less broken. On the same time strong magnetic field quickly induces chiral symmetry breaking even at the presence of fixed gravitational field within nonbroken phase.Comment: 23 pages, Latex, epic.sty and eepic.sty are use

Dynamical symmetry breaking in the Nambu-Jona-Lasino model with external gravitational and constant electric fields

An investigation of the Nambu-Jona-Lasino model with external constant electric and weak gravitational fields is carried out in three- and four- dimensional spacetimes. The effective potential of the composite bifermionic fields is calculated keeping terms linear in the curvature, while the electric field effect is treated exactly by means of the proper- time formalism. A rich dynamical symmetry breaking pattern, accompanied by phase transitions which are ruled, independently, by both the curvature and the electric field strength is found. Numerical simulations of the transitions are presented.Comment: 20 pages, LaTeX, 6 .ps-figures, Final version published in "Classical and Quantum Gravity