We study numerically the probability distribution of the Yang-Lee zeroes inside the Griffiths phase for the two dimensional site diluted Ising model and we check that the shape of this distribution is that predicted in previous analytical works. By studying the finite size scaling of the averaged smallest zero at the phase transition we extract, for two values of the dilution, the anomalous dim...

What is known today as the Lee-Friedrichs model is characterized by a self-adjoint operator H on a Hilbert space H, which is the sum of two self-adjoint operators H0 and V , such that H,H0 and V have common domain; H0 has absolutely continuous spectrum (of uniform multiplicity) except for the end-point of the semi-bounded from below spectrum, and one or more eigenvalues which may or may not be ...

We study a phase transition in a non-equilibrium model first introduced in [5], using the Yang-Lee description of equilibrium phase transitions in terms of both canonical and grand canonical partition function zeros. The model consists of two different classes of particles hopping in opposite directions on a ring. On the complex plane of the diffusion rate we find two regions of analyticity for...

To operate effectively in complex environments learning agents have to selectively ignore irrelevant details by forming useful abstractions. In this paper we outline a formulation of abstraction for reinforcement learning approaches to stochastic decision problems by extending one of the recent minimization models, known as ǫ-reduction. The technique presented here extends ǫ-reduction to SMDPs ...

Chen (1996) has recently shown how the response matrix of a two-phase composite can be written as certain linear combinations of products of the component matrices. We elaborate on Chen's expansions by deriving them in a different way, which a. shows them in a different light, and b. permits us to generalize them further. As an application of our results we find exact microstructure-independent...

Using finite-size-scaling methods, we study the quantum chain version of the spin-1-Blume-Capel model coupled to an imaginary field. The aim is to realize higher order nonunitary conformal field theories in a simple Ising-type spin model. We find that the first groundstate level crossing in the high-temperature phase leads to a second-order phase transition of the Yang-Lee universality class (c...

[1] We present a hypothesis that the known formation of nitric acid hydrates in lee-wave ice clouds produces a ‘‘standing crop’’ of nitric acid trihydrate (NAT) particles, and that growth and sedimentation of these particles efficiently denitrifies the polar stratosphere. Simulations using a simple two-dimensional model illustrate that the large NAT number concentrations produced in lee waves (...

Term structure models describe the evolution of the yield curve through time, without considering the influence of risk, tax, etc. Recently, uncertain processes were initialized and applied to option pricing and currency model. Under the assumption of short interest rate following uncertain processes, this paper investigates the term-structure equation. This equation is first derived for valuin...