Inhomogeneous spacetimes in Weyl integrable geometry with matter source

We investigate the existence of inhomogeneous exact solutions in Weyl Integrable theory with a matter source. In particular, we consider the existence of a dust fluid source while for the underlying geometry we assume a line element which belongs to the family of silent universes. We solve explicitly the field equations and we find the Szekeres spacetimes in Weyl Integrable theory. We show that only the isotropic family can describe inhomogeneous solutions where the LTB spacetimes are included. A detailed analysis of the dynamics of the field equations is given where the past and future attractors are determined. It is interesting that the Kasner spacetimes can be seen as past attractors for the gravitation models, while the unique future attractor describes the Milne universe similar with the behaviour of the gravitational model in the case of General Relativity.

Replica approach in random matrix theory

This article examines the replica method in random matrix theory (RMT), with particular emphasis on recently discovered integrability of zero-dimensional replica field theories. It first provides an overview of both fermionic and bosonic versions of the replica limit, along with its trickery, before discussing early heuristic treatments of zero-dimensional replica field theories, with the goal of advocating an exact approach to replicas. The latter is presented in two elaborations: by viewing the β = 2 replica partition function as the Toda lattice and by embedding the replica partition function into a more general theory of τ functions. The density of eigenvalues in the Gaussian Unitary Ensemble (GUE) and the saddle point approach to replica field theories are also considered. The article concludes by describing an integrable theory of replicas that offers an alternative way of treating replica partition functions.

Orthogonal Polynomials in Mathematical Physics

This is a review of ([Formula: see text]-)hypergeometric orthogonal polynomials and their relation to representation theory of quantum groups, to matrix models, to integrable theory, and to knot theory. We discuss both continuous and discrete orthogonal polynomials, and consider their various generalizations. The review also includes the orthogonal polynomials into a generic framework of ([Formula: see text]-)hypergeometric functions and their integral representations. In particular, this gives rise to relations with conformal blocks of the Virasoro algebra. To the memory of Ludwig Dmitrievich Faddeev

ON A CLASS OF INTEGRABLE SYSTEMS CONNECTED WITH GL(N,ℝ)

In this paper we define a new class of the quantum integrable systems associated with the quantization of the cotangent bundle T*(GL(N)) to the Lie algebra [Formula: see text]. The construction is based on the Gelfand-Zetlin maximal commuting subalgebra in [Formula: see text]. We discuss the connection with the other known integrable systems based on T*GL(N). The construction of the spectral tower associated with the proposed integrable theory is given. This spectral tower appears as a generalization of the standard spectral curve for an integrable system.

LANDAU-GINZBURG TOPOLOGICAL THEORIES IN THE FRAMEWORK OF GKM AND EQUIVALENT HIERARCHIES

We consider the deformations of "monomial solutions" to generalized Kontsevich. model1,2 and establish the relation between the flows generated by these deformations with those of N = 2 Landau-Ginzburg topological theories. We prove that the partition function of a generic generalized Kontsevich model can be presented as a product of some "quasiclassical" factor and non-deformed partition function which depends only on the sum of Miwa transformed and flat times. This result is important for the restoration of explicit p − q symmetry in the interpolation pattern between all the (p, q)-minimal string models with c < 1 and for revealing its integrable structure in p-direction, determined by deformations of the potential. It also implies the way in which supersymmetric LandauGinzburg models are embedded into the general context of GKM. From the point of view of integrable theory these deformations present a particular case of what is called equivalent hierarchies.