17 research outputs found
Renormalized effective actions for the O(N) model at next-to-leading order of the 1/N expansion
A fully explicit renormalized quantum action functional is constructed for
the O(N)-model in the auxiliary field formulation at next-to-leading order
(NLO) of the 1/N expansion. Counterterms are consistently and explicitly
derived for arbitrary constant vacuum expectation value of the scalar and
auxiliary fields. The renormalized NLO pion propagator is exact at this order
and satisfies Goldstone's theorem. Elimination of the auxiliary field sector at
the level of the functional provides with order N^0 accuracy the renormalized
effective action of the model in terms of the original variables. Alternative
elimination of the pion and sigma propagators provides the renormalized NLO
effective potential for the expectation values of the N-vector and of the
auxiliary field with the same accuracy.Comment: RevTeX4, 19 pages, 3 figures. Version published Phys. Rev.
Two-part set systems
The two part Sperner theorem of Katona and Kleitman states that if is an
-element set with partition , and \cF is a family of subsets
of such that no two sets A, B \in \cF satisfy (or ) and for some , then |\cF| \le {n
\choose \lfloor n/2 \rfloor}. We consider variations of this problem by
replacing the Sperner property with the intersection property and considering
families that satisfiy various combinations of these properties on one or both
parts , . Along the way, we prove the following new result which may
be of independent interest: let \cF, \cG be families of subsets of an
-element set such that \cF and \cG are both intersecting and
cross-Sperner, meaning that if A \in \cF and B \in \cG, then and . Then |\cF| +|\cG| < 2^{n-1} and there are
exponentially many examples showing that this bound is tight
High Energy Neutrinos and Photons from Curvature Pions in Magnetars
We discuss the relevance of the curvature radiation of pions in strongly
magnetized pulsars or magnetars, and their implications for the production of
TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as
high energy photons.Comment: 19 pages, 4 figures, to appear in JCA
Chiral and Gluon Condensates at Finite Temperature
We investigate the thermal behaviour of gluon and chiral condensates within
an effective Lagrangian of pseudoscalar mesons coupled to a scalar glueball.
This Lagrangian mimics the scale and chiral symmetries of QCD. (Submitted to Z.
Phys. C)Comment: 20 pages + 7 figures (uuencoded compressed postscript files),
University of Regensburg preprint TPR-94-1
A microscopic semiclassical confining field equation for lattice gauge theory in 2+1 dimensions
We present a semiclassical nonlinear field equation for the confining field
in 2+1--dimensional lattice gauge theory (compact QED). The equation is
derived directly from the underlying microscopic quantum Hamiltonian by means
of truncation. Its nonlinearities express the dynamic creation of magnetic
monopole currents leading to the confinement of the electric field between two
static electric charges. We solve the equation numerically and show that it can
be interpreted as a London relation in a dual superconductor.Comment: 21 pages, epsf postscript figures included, full postscript available
at ftp://ftp.th.physik.uni-frankfurt.de/pub/cbest/micro.ps.Z or
http://www.th.physik.uni-frankfurt.de/~cbest/pub.htm
Phase transitions in quantum chromodynamics
The current understanding of finite temperature phase transitions in QCD is
reviewed. A critical discussion of refined phase transition criteria in
numerical lattice simulations and of analytical tools going beyond the
mean-field level in effective continuum models for QCD is presented.
Theoretical predictions about the order of the transitions are compared with
possible experimental manifestations in heavy-ion collisions. Various places in
phenomenological descriptions are pointed out, where more reliable data for
QCD's equation of state would help in selecting the most realistic scenario
among those proposed. Unanswered questions are raised about the relevance of
calculations which assume thermodynamic equilibrium. Promising new approaches
to implement nonequilibrium aspects in the thermodynamics of heavy-ion
collisions are described.Comment: 156 pages, RevTex. Tables II,VIII,IX and Fig.s 1-38 are not included
as postscript files. I would like to ask the requestors to copy the missing
tables and figures from the corresponding journal-referenc
Photometric study of the contact binary star V861 Herculis
First Cousins light curves of the W UMa-type eclipsing variable star V861 Herculi