461 research outputs found
Effects in Chern-Simons with a Four-Fermi Interaction
We investigate the effects of the Chern-Simons coupling on the high energy
behavior in the -dimensional Chern-Simons QED with a four-Fermi
interaction. Using the expansion we discuss the Chern-Simons effects on
the critical four-Fermi coupling at and the function around
it. High-energy behavior of Green's functions is also discussed. By explicit
calculation, we find that the radiative correction to the Chern-Simons coupling
vanishes at in the broken phase of the dynamical parity symmetry. We
argue that no radiative corrections to the Chern-Simons term arise at higher
orders in the expansion.Comment: 13 pages, 6 figures not included, LaTeX, SNUTP 92-9
Comparing the unmatched count technique and direct self-report for sensitive health-risk behaviors in HIV+ adults
Researchers often rely on self-report measures to assess sensitive health-risk behaviors in HIV+ individuals, yet the accuracy of self-report has been questioned, particularly when inquiring about behaviors that may be embarrassing, risky, and/or taboo. We compared an anonymous reporting methodâthe Unmatched Count Technique (UCT)âto direct self-report in order to assess reporting differences for several health-risk behaviors related to medication adherence and sexual risk. Contrary to hypotheses, the UCT only produced a significantly higher estimated base rate for one sensitive behavior: reporting medication adherence to one\u27s physician, which may have been contextually-primed by our study design. Our results suggest that anonymous reporting methods may not increase disclosure compared to direct self-report when assessing several health-risk behaviors in HIV+ research volunteers. However, our results also suggest that contextual factors should be considered and investigated further, as they may influence perception of sensitive behavior
On Topologically Massive Spin-2 Gauge Theories beyond Three Dimensions
We investigate in which sense, at the linearized level, one can extend the 3D
topologically massive gravity theory beyond three dimensions. We show that, for
each k=1,2,3... a free topologically massive gauge theory in 4k-1 dimensions
can be defined describing a massive "spin-2" particle provided one uses a
non-standard representation of the massive "spin-2" state which makes use of a
two-column Young tableau where each column is of height 2k-1. We work out the
case of k=2, i.e. 7D, and show, by canonical analysis, that the model
describes, unitarily, 35 massive "spin-2" degrees of freedom. The issue of
interactions is discussed and compared with the three-dimensional situation.Comment: 14 pages. v2: minor changes - published versio
Central charge and renormalization in supersymmetric theories with vortices
Some quantum features of vortices in supersymmetric theories in 1+2
dimensions are studied in a manifestly supersymmetric setting of the superfield
formalism. A close examination of the supercurrent that accommodates the
central charge and super-Poincare charges in a supermultiplet reveals that
there is no genuine quantum anomaly in the supertrace identity and in the
supercharge algebra, with the central-charge operator given by the bare
Fayet-Iliopoulos term alone. The central charge and the vortex spectrum undergo
renormalization on taking the expectation value of the central-charge operator.
It is shown that the vortex spectrum is exactly determined at one loop while
the spectrum of the elementary excitations receives higher-order corrections.Comment: 9 pages, revte
Renormalization Group Study of Chern-Simons Field Coupled to Scalar Matter in a Modified BPHZ Subtraction Scheme
We apply a soft version of the BPHZ subtraction scheme to the computation of
two-loop corrections from an Abelian Chern-Simons field coupled to (massive)
scalar matter with a and
self-interactions. The two-loop renormalization group functions are calculated.
We compare our results with those in the literature.Comment: 15 pages, 7 figures, revtex. To appear in Phys. Rev.
Gravitational anomaly and fundamental forces
I present an argument, based on the topology of the universe, why there are
three generations of fermions. The argument implies a preferred gauge group of
SU(5), but with SO(10) representations of the fermions. The breaking pattern
SU(5) to SU(3)xSU(2)xU(1) is preferred over the pattern SU(5) to SU(4)xU(1). On
the basis of the argument one expects an asymmetry in the early universe
microwave data, which might have been detected already.Comment: Contribution to the 2nd School and Workshop on Quantum Gravity and
Quantum Geometry. Corfu, september 13-20 2009. 10 page
The Chern-Simons Coefficient in Supersymmetric Non-abelian Chern-Simons Higgs Theories
By taking into account the effect of the would be Chern-Simons term, we
calculate the quantum correction to the Chern-Simons coefficient in
supersymmetric Chern-Simons Higgs theories with matter fields in the
fundamental representation of SU(n). Because of supersymmetry, the corrections
in the symmetric and Higgs phases are identical. In particular, the correction
is vanishing for N=3 supersymmetric Chern-Simons Higgs theories. The result
should be quite general, and have important implication for the more
interesting case when the Higgs is in the adjoint representation.Comment: more references and explanation about rgularization dpendence are
included, 13 pages, 1 figure, latex with revte
The Kramers equation simulation algorithm II. An application to the Gross-Neveu model
We continue the investigation on the applications of the Kramers equation to
the numerical simulation of field theoretic models. In a previous paper we have
described the theory and proposed various algorithms. Here, we compare the
simplest of them with the Hybrid Monte Carlo algorithm studying the
two-dimensional lattice Gross-Neveu model. We used a Symanzik improved action
with dynamical Wilson fermions. Both the algorithms allow for the determination
of the critical mass. Their performances in the definite phase simulations are
comparable with the Hybrid Monte Carlo. For the two methods, the numerical
values of the measured quantities agree within the errors and are compatible
with the theoretical predictions; moreover, the Kramers algorithm is safer from
the point of view of the numerical precision.Comment: 20 pages + 1 PostScript figure not included, REVTeX 3.0, IFUP-TH-2
Massless Scalar QED with Non-minimal Chern Simons Coupling
2+1 dimensional massless scalar QED with scalar
self-coupling is modified by the addition of a non- minimal Chern-Simons term
that couples the dual of the electromagnetic field strength to the covariant
current of the complex scalar field. The theory is shown to be fully one- loop
renormalizable. The one loop effective potential for the scalar field gives
rise to spontaneous symmetry breaking which induces masses for both the scalar
and vector fields. At high temperature there is a symmetry restoring phase
transition.Comment: 18 pages, latex, preprint WIN-93-1
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