538 research outputs found
Shift versus no-shift in local regularizations of Chern-Simons theory
We consider a family of local BRS-invariant higher covariant derivative
regularizations of Chern-Simons theory that do not shift the value of
the Chern-Simons parameter to k+\,{\rm sign}(k)\,\cv at one loop.Comment: phyzzx, 6 pages, FTUAM 94/8, NIKHEF-H 94/14 and UPRF 93/39
Supersymmetric Yang-Mills-Chern-Simons theory
We prove that three-dimensional N=1 supersymmetric Yang-Mills-Chern-Simons
theory is finite to all loops. This leaves open the possibility that different
regularization methods give different finite effective actions. We show that
for this model dimensional regularization and regularization by dimensional
reduction yield the same effective action.Comment: 6 pages, 1 figure, latex, espcrc2. Contribution to the Proceedings of
the 30th Ahrenshoop Symposium on the Theory of Elementary Particles, edited
by D. Lust, H.-J. Otto and G. Weigt, to appear in Nuclear Physics B,
Proceedings Supplemen
The Role of Ivabradine in the Management of Angina Pectoris
Stable angina pectoris affects 2–4 % of the population in Western countries and entails an annual risk of death and nonfatal myocardial infarction of 1–2 % and 3 %, respectively. Heart rate (HR) is linearly related to myocardial oxygen consumption and coronary blood flow, both at rest and during stress. HR reduction is a key target for the prevention of ischemia/angina and is an important mechanism of action of drugs which are recommended as first line therapy for the treatment of angina in clinical guidelines. However, many patients are often unable to tolerate the doses of beta blocker or non-dihydropyridine calcium antagonists required to achieve the desired symptom control. The selective pacemaker current inhibitor ivabradine was developed as a drug for the management of patients with angina pectoris, through its ability to reduce HR specifically. The available data suggest that ivabradine is a well-tolerated and effective anti-anginal agent and it is recommended as a second-line agent for relief of angina in guidelines. However, recent clinical trials of ivabradine have failed to show prognostic benefit and have raised potential concerns about safety. This article will review the available evidence base for the current role of ivabradine in the management of patients with symptomatic angina pectoris in the context of stable coronary artery disease
The universality of the shift of the Chern-Simons parameter for a general class of BRS invariant regularizations
We consider a biparametric family of BRS invariant regularization methods of
SU(N) Chern-Simons theory (the parameters defining the family taking arbitrary
values in \RR^2) and show that the shift of the
Chern-Simons parameter occurs for arbitrary values of the family defining
parameters. This supports irrefutably the conjecture that the shift of is
universal for BRS invariant regulators.Comment: phyzzx, 7 pages (no figures
Regularization and Renormalization of Chern-Simons Theory
We analyze some features of the perturbative quantization of Chern-Simons
theory (CST) in the Landau gauge. In this gauge the theory is known to be
perturbatively finite. We consider the renormalization scheme in which the
renormalized parameter equals the bare or classical one and show that it
constitutes a natural parametrization for the quantum theory. The reason is
that, although in this renormalization scheme the value of the Green functions
depends on the regularization used, comparison among different regularization
methods shows that the observables (Wilson loops) are the same function of the
shifted monodromy parameter for all BRS invariant regulators used so
far for CST. We also discuss a particular BRS invariant regularization
prescription in which CST is perturbatively defined as the large mass limit of
dimensionally regularized topologically massive Yang-Mills theory. With this
regularization prescription the radiative corrections induced by two-loop
contributions do not entail observable consequences since they can be
reabsorbed by a finite rescaling of the fields only. This very mechanism is
conjectured to take place at higher perturbative orders. Talk presented by G.G.
at the NATO AWR on ``Low dimensional Topology and Quantum Field Theory'', 6-13
September 1992, Cambridge (UK).Comment: 10 pages, Phyzzx, LPTHE 92-4
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