We study the perturbation theory for three dimensional Chern–Simons quantum field theory on a general compact three manifold without boundary. We show that after a simple change of variables, the action obtained by BRS gauge fixing in the Lorentz gauge has a superspace formulation. The basic properties of the propagator and the Feynman rules are written in a precise manner in the language of di...

A short overview of the current state of Chiral Perturbation Theory is given. This includes a description of the basic assumptions, the usefulness of the external field method is emphasized using a simple lowest order example. Then at next-to-leading order the determination of the parameters is discussed. We also present the status of calculations at O(p6). Finally I present the extension into ...

A method is suggested for treating those complicated physical problems for which exact solutions are not known but a few approximation terms of a calculational algorithm can be derived. The method permits one to answer the following rather delicate questions: What can be said about the convergence of the calculational procedure when only a few its terms are available and how to decide which of ...

When we apply the steady-state approximation (SSA) in chemical kinetics, we typically argue that some of the intermediates are highly reactive, so that they are removed as fast as they are made. We then set the corresponding rates of change to zero. What we are saying is not that these rates are identically zero, of course, but that they are much smaller than the other rates of reaction. The st...

The variational formulation for Lie-transform Hamiltonian perturbation theory is presented in terms of an action functional defined on a two-dimensional parameter space. A fundamental equation in Hamiltonian perturbation theory is shown to result from the freedom of choice of the integration path for the action functional.

The large k asymptotics (perturbation series) for integrals of the form ∫ F μe ikS , where μ is a smooth top form and S is a smooth function on a manifold F , both of which are invariant under the action of a symmetry group G, may be computed using the stationary phase approximation. This perturbation series can be expressed as the integral of a top form on the space M of critical points of S m...

We develop a perturbation method that generalizes an approach proposed recently to treat velocity–dependent quantum–mechanical models. In order to test present approach we apply it to some simple trivial and nontrivial examples. PACS. 03.65.Ge Solutions of wave equations: bound states

A form of stochastic perturbation theory is described, where the representative stochastic fields are generated instantaneously rather than through a Markov process. The correctness of the procedure is established to all orders of the expansion and for a wide class of field theories that includes all common formulations of lattice QCD.

The double angle theorems of Davis and Kahan bound the change in an invariant subspace when a Hermitian matrix A is subject to an additive perturbation A ! e A = A+A. This paper supplies analogous results when A is subject to a congruential, or multiplicative, perturbation A ! e A = D AD. The relative gaps that appear in the bounds involve the spectrum of only one matrix, either A or e A, in co...

BES II data for J/Ψ → K * (890)Kπ reveal a strong κ peak in the Kπ S-wave near threshold. Both magnitude and phase are determined in slices of Kπ mass by interferences with strong K 0 (1430), K 1 (1270) and K 1 (1400) signals. The phase variation with mass agrees within errors with LASS data for Kπ elastic scattering. A combined fit is presented to both BES and LASS data. The fit uses a Breit-W...