[en] We study relations between quantum sl(n) and quantum sl(k) when q^n+k = ± 1. We show that after restriction to type II representations, the commutant of U_qsl(n) in Y_nk^xL and the commutant of U_qsl(k) in ^tY_kn^xL (where Y is a Young tableau and ^tY its transpose with respect to NW-SE diagonal) are mapped into each other by R_nk → R_kn^-1. Applications to lattice integrable models and link polynomials are discussed. We show in particular that the link polynomials built from U_qsl(n), Y and U_qsl(k), ^tY take complex conjugate values when q^n+k = ± 1. (orig.)

[en] Using previous results on non-perturbative effects in massive supersymmetric Yang-Mills theories, we extend recent considerations on the duality invariant gaugino condensation, within the string effective action approach, to the formation of hidden matter field condensates. The masses of the condensing matter fields are determined by some string background parameters corresponding to vacuum expectation values of additional gauge singlet hidden matter fields. The vacuum degeneracy of these fields is shown to be lifted by non-perturbative condensation effects. (orig.)

[en] The vacuum energy for an open and a closed superstring is calculated in the M-tilde₄xT₆ background at nonzero temperature and for the choice of different boundary conditions for bosons and fermions along a few compactified dimensions on a torus. The vacuum energy for the closed string is transformed to the modular-invariant form. The coincidence of the vacuum energies of the superstring on M-tilde₄xT₆ with different boundary conditions along 5, ..., k dimensions and of the superstring on M₃xT₇ at zero temperature and different boundary conditions along 5, ..., k+1 dimensions are demonstrated

[en] In this article we want to explain how groups are used in quantum physics. We use the simplest example, the rigid rotator. In Sect. 1 we briefly review of quantum mechanical notions. Section 2 presents the symmetry group, Sect. 3 the spectrum generating group in nonrelativistic physics. Section 4 describes how these ideas can be generalized to the nonrelativistic case, when the combination of symmetry group and spectrum generating group is no more trivial. (orig./HSI)

[en] We define a topological action of the quantum group U_q(sl₂) on a space of homology cycles with twisted coefficients on the configuration space of the punctured disc. This action commutes with the monodromy action of the braid groupoid, which is given by the R-matrix of U_q(sl₂). (orig.)

[en] We consider a broad class of Kaehler supersymmetric sigma models in two-dimensional space-time. The exact Gell-Mann-Low function is found within the framework of the method proposed earlier and based on analysis of classical solutions. It is shown that the exact beta function accounting for all orders in the coupling constant actually coincides with the one-loop result. (orig.)

[en] The derivation of the representations of BRS algebra in the Landau gauge is simplified by the superspace formalism. It is shown that the operation of the metric matrix can be interpreted as a kind of inversion of the superspace. (orig.)

[en] Du, Dunietz, and Wu examined CP violation in partial-decay-rate asymmetries of neutral b-flavored mesons in the standard Kobayashi-Maskawa (KM) model. We calculate in the four-generation model the same CP asymmetry in B_d hadronic decays in light of the large B_d-bar B_d mixing obtained by the ARGUS and CLEO Collaborations. The general 4x4 KM matrix proposed by Botella and Chau is used. The effect of the fourth generation on asymmetry is found to be sizable for various mixings of the fourth with the preceding three generations, changing signs of the asymmetry in the modes bar b→ bar uu bar d and bar b→ bar cc bar d, and enhancing magnitudes in the modes bar b→ bar uc bar d and bar b→ bar cu bar d from their standard-model predictions

[en] A (1 + 1)-dimensional lattice U(1) gauge model is solved exactly and the result shows that this model has correct continuum limit

[en] A 1 + 1-dimensional U(1) gauge theory is proposed and the exact solution of its spectrum and corresponding energy eigenstates is found