[en] We propose an algebraic description of (untwisted) D-branes on compact group manifolds G using quantum algebras related to U_q(g). It reproduces the known characteristics of stable branes in the WZW models, in particular their configurations in G, energies as well as the set of harmonics. Both generic and degenerate branes are covered

[en] Short communication

No abstract available

[en] Some renormalization group approaches have been proposed during the last few years which are close in spirit to the Nightingale phenomenological procedure. In essence, by exploiting the finite sized scaling hypothesis, the approximate critical behavior of model on finite lattice is obtained through the exact, computation of some thermal quantities of the model on finite clusters. In this work some of these methods are reviewed, namely the mean field renormalization group, the effective field renormalization group and the finite size scaling renormalization group procedures. Although special emphasis is given to the mean field renormalization group and the finite size scaling renormalization group procedures. Although special emphasis is given to the mean field renormalization group (since it has been, up to now much more used to study a wide variety of different systems) a discussion of their potentialities and interrelations to other methods is also presented. (author)

[en] Short communication

[en] We present the results of the first direct determination of the g_D*Dπ coupling using lattice QCD. From our simulations in the quenched approximation, we obtain g_D*Dπ = 18.8 ± 2.3_-2.0^+1.1 and g-circumflex = 0.67 ± 0.08_-0.06^+0.04. It is in agreement with a recent experimental result from CLEO

[en] The issue of (non) triviality of (λ₀φ⁴)_s+1 where s denotes the space dimension, and λ₀ the 'bare' coupling constant, remain as one of the most important conceptual questions in quantum field theory. In this note we summarize some of the ideas in two recent papers. Unfortunately, there are no rigorous results on triviality for 3 = 3. It is also important to compare this case, which is conventionally renormalizable with s = 2, which is super renormalizable. Folklore predicts triviality in the former-case, and non triviality in the later. Our basic result concerns the so called Lee approximation

[en] The thermodynamics of the massive λ φ ⁴ + σ φ ⁶ model is analysed at finite temperature in the two-loop approximation. The behavior of the thermal mass and coupling constant is discussed. We demonstrate in the two-loops approximation the existence of a tricritical point. (author). 23 refs., 4 figs

No abstract available

No abstract available