Three-Loop Calculation of the Anyonic Full Cluster Expansion

We calculate the perturbative correction to every cluster coefficient of a gas of anyons through second order in the anyon coupling constant, as described by Chern-Simons field theory.Comment: 10 pages, PlainTex with macro 'manumac', include

Bayesian Model Selection for Beta Autoregressive Processes

We deal with Bayesian inference for Beta autoregressive processes. We restrict our attention to the class of conditionally linear processes. These processes are particularly suitable for forecasting purposes, but are difficult to estimate due to the constraints on the parameter space. We provide a full Bayesian approach to the estimation and include the parameter restrictions in the inference problem by a suitable specification of the prior distributions. Moreover in a Bayesian framework parameter estimation and model choice can be solved simultaneously. In particular we suggest a Markov-Chain Monte Carlo (MCMC) procedure based on a Metropolis-Hastings within Gibbs algorithm and solve the model selection problem following a reversible jump MCMC approach

Large lepton mixing and supernova 1987A

We reconsider the impact of $\bar\nu_e \leftrightarrow \bar\nu_{\mu,\tau}$ neutrino oscillations on the observed $\bar\nu_e$ signal of supernova SN 1987A. Performing a maximum-likelihood analysis using as fit parameters the released binding energy \Eb and the average neutrino energy \Ee, we find as previous analyses that $\bar\nu_e \leftrightarrow \bar\nu_{\mu,\tau}$ oscillations with large mixing angles have lower best-fit values for \Ee than small-mixing angle (SMA) oscillations. Moreover, the inferred value of \Ee is already in the SMA case lower than those found in simulations. This apparent conflict has been interpreted as evidence against the large mixing oscillation solutions to the solar neutrino problem. In order to quantify the degree to which the experimental data favour the SMA over the large mixing solutions we use their likelihood ratios as well as a Kolmogorov-Smirnov test. We find within the range of SN parameters predicted by simulations regions in which the LMA-MSW solution is either only marginally disfavoured or favoured compared to the SMA-MSW solution. We conclude therefore that the LMA-MSW solution is not in conflict with the current understanding of SN physics. In contrast, the vacuum oscillation and the LOW solutions to the solar neutrino problem can be excluded at the $4\sigma$ level for most of the SN parameter ranges found in simulations. Only a marginal region with low values of \Ee, $$ and \Eb is left over, in which these oscillation solutions can be reconciled with the neutrino signal of SN 1987A.Comment: 23 pages, 20 figures, v2: brief comments adde

Scattering of accelerated wave packets

Wave-packet scattering from a stationary potential is significantly modified when the wave-packet is subject to an external time-dependent force during the interaction. In the semiclassical limit, wave--packet motion is simply described by Newtonian equations and the external force can, for example, cancel the potential force making a potential barrier transparent. Here we consider wave-packet scattering from reflectionless potentials, where in general the potential becomes reflective when probed by an accelerated wave-packet. In the particular case of the recently-introduced class of complex Kramers-Kronig potentials we show that a broad class of time dependent forces can be applied without inducing any scattering, while there is a breakdown of the reflectionless property when there is a broadband distribution of initial particle momentum, involving both positive and negative components.Comment: 13 pages, 4 figures, to appear in Phys. Rev.

Computation of the equilibrium composition of reacting gas-solid mixtures with material and energy balance constraints Status report

Equilibrium composition computed for reacting- gas-solid composite materials using material and energy constraint