Induced Dilaton in Topologically Massive Quantum Field Theory

We consider the conformally-invariant coupling of topologically massive gravity to a dynamical massless scalar field theory on a three-manifold with boundary. We show that, in the phase of spontaneously broken Lorentz and Weyl symmetries, this theory induces the target space zero mode of the vertex operator for the string dilaton field on the boundary of the three-dimensional manifold. By a further coupling to topologically massive gauge fields in the bulk, we demonstrate directly from the three-dimensional theory that this dilaton field transforms in the expected way under duality transformations so as to preserve the mass gaps in the spectra of the gauge and gravitational sectors of the quantum field theory. We show that this implies an intimate dynamical relationship between T-duality and S-duality transformations of the quantum string theory. The dilaton in this model couples bulk and worldsheet degrees of freedom to each other and generates a dynamical string coupling.Comment: 26 pages RevTeX, 1 figure, uses epsf.st

Involvement of Nitric Oxide in Microcirculatory Reactions after Ischemia-Reperfusion of the Rat Urinary Bladder

Background: Nitric oxide ( NO) plays a role in inflammation. Our aim was to investigate the role of NO in the microcirculatory changes after ischemia-reperfusion (I/R) of the bladder using intravital videomicroscopy (IVM). Methods: In rats, 60 min of bladder ischemia followed by 30 min of reperfusion was performed in the presence of N(G)-nitro-L-arginine methyl ester (L-NAME), the NO precursor L-arginine, or saline pre-treatments. Venular red blood cell velocity (RBCV), functional capillary density (FCD), vessel diameters, and leukocyte-endothelial cell interactions in postcapillary venules were determined. Concentrations of nitrite/nitrate in the plasma and myeloperoxidase (MPO) levels in the lungs and the bladder were measured. Results: Elevations of the numbers of rolling and adherent leukocytes, and of plasma nitrite/nitrate levels were found, while FCD and RBCV decreased. L-NAME pretreatment ameliorated the enhanced leukocyte-endothelial cell interactions without influencing the microcirculatory perfusion. In contrast, the L - arginine pretreatment further increased plasma nitrite/nitrate levels and preserved the FCD and RBCV, but did not affect leukocyte-endothelial interactions. None of these treatments influenced MPO activities. Conclusion: Our results suggest that NO plays an enhancing role in the I/R-induced neutrophil-endothelial interactions of the bladder. Supplementation of NO ameliorates the microcirculatory perfusion deficit without influencing the postischemic microcirculatory inflammatory reactions. Copyright (c) 2008 S. Karger AG, Base

Radiation Generated by Charge Migration Following Ionization

Electronic many-body effects alone can be the driving force for an ultrafast migration of a positive charge created upon ionization of molecular systems. Here we show that this purely electronic phenomenon generates a characteristic IR radiation. The situation when the initial ionic wave packet is produced by a sudden removal of an electron is also studied. It is shown that in this case a much stronger UV emission is generated. This emission appears as an ultrafast response of the remaining electrons to the perturbation caused by the sudden ionization and as such is a universal phenomenon to be expected in every multielectron system.Comment: 5 pages, 4 figure

The QCD equation of state at finite T/\mu on the lattice

We present N_t=4 lattice results for the equation of state of 2+1 flavour staggered, dynamical QCD at finite temperature and chemical potential. We use the overlap improving multi-parameter reweighting technique to extend the equation of state for non-vanishing chemical potentials. The results are obtained along the line of constant physics. Our physical parameters extend in temperature and baryon chemical potential upto \approx 500-600 MeV.Comment: 13 pages 9 figures, talk given at Finite Density QCD at Nara, Nara, Japan, 10-12 July 200

Lattice QCD at non-vanishing density: phase diagram, equation of state

We propose a method to study lattice QCD at non-vanishing temperature (T) and chemical potential (\mu). We use n_f=2+1 dynamical staggered quarks with semi-realistic masses on L_t=4 lattices. The critical endpoint (E) of QCD on the Re(\mu)-T plane is located. We calculate the pressure (p), the energy density (\epsilon) and the baryon density (n_B) of QCD at non-vanishing T and \mu.Comment: Contributed to Workshop on Strong and Electroweak Matter (SEWM 2002), Heidelberg, Germany, 2-5 Oct 200

Post-Wick theorems for symbolic manipulation of second-quantized expressions in atomic many-body perturbation theory

Manipulating expressions in many-body perturbation theory becomes unwieldily with increasing order of the perturbation theory. Here I derive a set of theorems for efficient simplification of such expressions. The derived rules are specifically designed for implementing with symbolic algebra tools. As an illustration, we count the numbers of Brueckner-Goldstone diagrams in the first several orders of many-body perturbation theory for matrix elements between two states of a mono-valent system.Comment: J. Phys. B. (in press); Mathematica packages available from http://wolfweb.unr.edu/homepage/andrei/WWW-tap/mathematica.htm