UniversalR-matrix for quantized (super)algebras

For quantum deformations of finite-dimensional contragredient Lie (super)algebras we give an explicit formula for the universalR-matrix. This formula generalizes the analogous formulae for quantized semisimple Lie algebras obtained by M. Rosso, A. N. Kirillov, and N. Reshetikhin, Ya. S. Soibelman, and S. Z. Levendorskii. Our approach is based on careful analysis of quantized rank 1 and 2 (super)algebras, a combinatorial structure of the root systems and algebraic properties ofq-exponential functions. We don't use quantum Weyl group.     

A review of super riemannian space-time using differential forms

We analyse the content of curved super space-time, which consists of points labelled by four ordinary space-time variables and a set of anti-commuting quantities. A definition of a curved manifold including such variables is given, and a coordinate free formalism reviewed using the super space-time extended version of modern differential geometric techniques. Such a formalism allows the incorporation of internal symmetries in a geometric fashion. Finally we analyse the extended version of Einstein's source-free equation on this manifold, particularly in the linear approximation.     

Scaling properties of eden clusters in three and four dimensions

We study the scaling properties of noise reduced Eden clusters in three and four dimensions for variant B in the strip geometry. We find that the width W for large times behaves as a(s)g(L/s^d−1), where L is the width of the strip, s the noise reduction parameter, d the dimension of space, and a(s) a decreasing function of s, g is a scaling function with the property g(u)→1/2 as u→0 and g(u)u^x as u→∞, where χ is the roughness exponent. This scaling result leads to a new way of determining χ. In 3 dimensions, our numerical values for χ support a recent conjecture by Kim and Kosterlitz: χ = 2/(d + 2), and contradict all the former analytical conjectures. In 4 dimensions, we cannot distinguish between the conjectures of Kim and Kosterlitz and the conjecture of Wolf and Kertész, because large crossovers and finite size effects make the measurement of the exponents difficult.     

Generalizations of Maxwell (super)algebras by the expansion method

The Lie algebras expansion method is used to show that the four-dimensional spacetime Maxwell (super)algebras and some of their generalizations can be derived in a simple way as particular expansions of o(3,2)$o(3,2)$ and osp(N|4)$\mathit{osp}(N|4)$.     

Euclidean gauge fields in four dimensions from stochastic differential equations

Using a stochastic differential equation for field configurations in a three-dimensional space lattice, one proves existence of a euclidean theory for non-abelian gauge fields on the lattice. The theory is also shown to possess a scaling limit for the mass gap at weak coupling. The construction is extended in a less rigorous manner to a theory with fermions and gauge fields.     

On anomalous U(1) gauge theory in four dimensions

We discuss the consistency, unitarity and Lorentz invariance of an anomalous U(1) gauge theory in four dimensions. Our analysis is based on an effective low-energy action valid in the chiral symmetry broken phase. The allegedly bad properties of anomalous theories (except non-renormalizability) are examined. It is shown that, in the low-energy context, the theory can be consistently and unitarily quantised, and is formally Lorentz covariant.     

Covering and gluing of algebras and differential algebras

Extending work of Budzyński and Kondracki, we investigate coverings and gluings of algebras and differential algebras. We describe in detail the gluing of two quantum discs along their classical subspace, giving a C^*-algebra isomorphic to a certain Podleś sphere, as well as the gluing of U_q^1/2(sl₂)-covariant differential calculi on the discs.     

Invasion percolation between two sites in two, three, and four dimensions

The mass distribution of invaded clusters in non-trapping invasion percolation between an injection site and an extraction site has been studied, in two, three, and four dimensions. This study is an extension of the recent study focused on two dimensions by Araújo et al. [A.D. Araújo, T.F. Vasconcelos, A.A. Moreira, L.S. Lucena, J.S. Andrade Jr., Phys. Rev. E 72 (2005) 041404] with respect to higher dimensions. The mass distribution exhibits a power-law behavior, P(m)∝m^−α. It has been found that the index α for p_e<p_c, p_c being the percolation threshold of a regular percolation, appears to be independent of the value of p_e and is also independent of the lattice dimensionality. When p_e=p_c, α appears to depend marginally on the lattice dimensionality, and the relation α=τ−1, τ being the exponent associated with cluster size distribution of a regular percolation via n_s∝s^−τ, appears to be valid.     

Finite lattice Z(3) models in two and three dimensions

We obtain the exact partition functions for finite lattice Z(3) models in two and three dimensions. We find the zeros of these partition functions in complex coupling constant space and interpret their positions in terms of the phase transitions of these models.     

Gauge Invariance of Banks-Peskin differential forms (flat background)

We discuss some aspects of the gauge invariance of Banks-Peskin differential forms on a flat background.     

Wilson loops for U(4) and SU(4) lattice gauge theories in four dimensions

Monte Carlo simulations are used to calculate Wilson loops for pure U(4) and SU(4) gauge theories on a 6⁴ lattice. The first-order phase transitions previously observed in the average action per plaquette for U(4) and SU(4) is also seen in the string tension. U(4) and SU(4) color seem to be confined while U(4) charge in U(4) appears to be deconfined.     

Instantons in two and four dimensions

It is shown that Yang-Mills instantons in four dimensions can naturally be identified with the instantons of a two-dimensional theory with values in the loop group.     

Density ofZ(3) flux loops inSU(3) lattice gauge theory in four dimensions

A mixed actionSU(3)-SU(3)/Z(3) gauge theory is simulated by Monte Carlo methods on a 4⁴ lattice. The density ofZ(3) flux loops is measured.     

Differential algebras andD-modules in super toda lattice hierarchy

A new super Toda lattice hierarchy is proposed and formulated in the language of differential algebra. AD-module structure is shown to exist behind this nonlinear system and to play the same role as a similarD-module for the super KP hierarchy. From the structure of thisD-module, one can indeed see a direct connection with a set of affine coordinates on an infinite-dimensional super Grassmannian manifold. These affine coordinates are the basic ingredients of an intrinsic construction of functions as well as symmetries.     

A phase transition in SU(5) lattice gauge theory in four dimensions

Monte Carlo simulations of the average action per plaquette are calculated for four-dimensional SU(5) gauge theory on a 3⁴ lattice. Evidence is found for a discontinuity in this order parameter which is a signal for a first-order phase transition.