Nontriviality of Abelian gauged Nambu-Jona-Lasinio models in four dimensions

We study a particular class of Abelian gauged Nambu-Jona-Lasinio models with global U_L(N)xU_R(N) symmetry, where N is the number of fermion flavors. We show, by treating the gauge interaction in the ladder approximation and four-fermion interactions in the leading order of the 1/N expansion, that the renormalization-group beta function of the U(1) gauge coupling has ultraviolet stable fixed points for sufficiently large N. This implies the existence of a nontrivial continuum limit.Comment: 44 pages, 10 figures, REVTeX, revised and corrected versio

Analytic structure of scalar composites in the symmetric phase of the gauged Nambu-Jona-Lasinio model

The gauged Nambu-Jona-Lasinio model in the quenched-ladder approximation has non-trivial dynamics near a critical scaling region (critical curve) separating a chiral symmetric and a dynamically chiral symmetry broken phase. Scalar and pseudoscalar composites corresponding to the four-fermion interaction become relevant degrees of freedom at short distances, which is reflected in the appearance of a large anomalous dimension of the four-fermion operators. A method is introduced for solving the Schwinger-Dyson equation for the Yukawa vertex in specific kinematic regimes. This allows one to derive an analytic expression for the scalar propagator, which is valid along the entire critical curve. The mass and width of the scalar composites in the critical scaling region are reexamined and the conformal phase transition at the critical gauge coupling is discussed.Comment: final version to appear in Phys. Rev.

Modelling galaxy stellar mass evolution from z~0.8 to today

We apply the empirical method built for z=0 in the previous work of Wang et al. to a higher redshift, to link galaxy stellar mass directly with its hosting dark matter halo mass at z~0.8. The relation of the galaxy stellar mass and the host halo mass M_infall is constrained by fitting both the stellar mass function and the correlation functions at different stellar mass intervals of the VVDS observation, where M_infall is the mass of the hosting halo at the time when the galaxy was last the central galaxy. We find that for low mass haloes, their residing central galaxies are less massive at high redshift than those at low redshift. For high mass haloes, central galaxies in these haloes at high redshift are a bit more massive than the galaxies at low redshift. Satellite galaxies are less massive at earlier times, for any given mass of hosting haloes. Fitting both the SDSS and VVDS observations simultaneously, we also propose a unified model of the M_stars-M_infall relation, which describes the evolution of central galaxy mass as a function of time. The stellar mass of a satellite galaxy is determined by the same M_stars-M_infall relation of central galaxies at the time when the galaxy is accreted. With these models, we study the amount of galaxy stellar mass increased from z~0.8 to the present day through galaxy mergers and star formation. Low mass galaxies gain their stellar masses from z~0.8 to z=0 mainly through star formation. For galaxies of higher mass, the increase of stellar mass solely through mergers from z=0.8 can make the massive galaxies a factor ~2 larger than observed at z=0. We can also predict stellar mass functions of redshifts up to z~3, and the results are consistent with the latest observations.Comment: 12 pages, 10 figures, accepted for publication in MNRA

Salvarsan encephalopathie:een clinisch en histopathologisch onderzoek, pathophysiologische beschouwingen

De salvarsan-encephalopathie (S.E.) is een aandoening met een kenmerkend clinisch beeld en karakteristieke liquorafwijkingen. Ook de histopathologie heeft een eigen aard. De ziekte is zeldzaam bij de gewone routinebehandeling in normale omstandigheden, maar treedt bij de moderne massieve behandeling, in bijzondere omstandigheden als tijden van oorlog en bij bepaalde mensengroepen veel frequenter op (Hoofdstuk I). Aan de hand van 5 eigen gevallen, van welke 3 letaal verliepen en ter obductie kwamen, werd de aandoening bestudeerd en daarbij werd een poging gedaan om uit het histopathologisch beeld en uit de clinische gegevens, in verband met de literatuur, inzich te verkrijgen aangaande het mechanisme, waardoor de ziekte tot stand komt. ... Zie: Samenvattin

Anomalous dimensions of gauge-invariant amplitudes in massless effective gauge theories of strongly correlated systems

We use the radial gauge to calculate the recently proposed ansatz for the physical electron propagator in such effective models of strongly correlated electron systems as the $QED_3$ theory of the pseudogap phase of the cuprates. The results of our analysis help to settle the recent dispute about the sign and the magnitude of the anomalous dimension which characterizes the gauge invariant amplitude in question and set the stage for computing other, more physically relevant, ones.Comment: Latex, 11 pages, no figure