From Braid Group Representations with Four Eigenvalues to Solutions of Yang-Baxter Equation

A recursive formula of Jimbo-type trigonometric Yang-Baxterization is presented. The consistency conditions of the Yang-Baxterization for four eigenvalues are obtained. Several 4 × 4 solutions of Yang-Baxter equations are obtained from a braid group representation.     

Link Polynomials and Hamiltonian Corresponding to Braid Group Representations of ZN Model

The more general braid group representations of ZZ_N model are given. Topologically invari-ant link polynomials related to the model are constructed. Here we present the simplest Hamiltonian with arbitrary coefficients of 1D quantum chain.     

Massless Fields as Unitary Representations of the Poincaré Group

Relativistic zero-mass fields are described as manifestly covariant unitary irreducible representations of the Poincaré group. The wave-equations, which are a necessary condition for unitarity, are constructed for spinor fields of arbitrary spin and for tensor fields of integer spin. Poincaré covariance together with causality and positive energy are used to determine the commutators of quantized fields up to a positive multiple and to prove the spin-statistics theorem. The use of potentials for boson fields is discussed and it is shown that, at the expense of manifest covariance, potentials may be introduced as zero-mass limits of the massive Wigner representations.     

A New Class of Representations of Braid Groups

In this letter, a new class of represen tations of the braid groups B_N, I_i-1⊕ T ⊕ I_N-i-1 is constructed. It is proved that those represen tations contain three kinds of irreducible representations: the trivial (identity) one, the Burau one, and a new N-dimensional one. The explicit form of the N-dimensional irreducible representation of the braid group B_N is given.     

Unitary Representations of Nilpotent Super Lie Groups

We show that irreducible unitary representations of nilpotent super Lie groups can be obtained by induction from a distinguished class of sub super Lie groups. These sub super Lie groups are natural analogues of polarizing subgroups that appear in classical Kirillov theory. We obtain a concrete geometric parametrization of irreducible unitary representations by nonnegative definite coadjoint orbits. As an application, we prove an analytic generalization of the Stone-von Neumann theorem for Heisenberg-Clifford super Lie groups.     

On Unitary Representations of Nilpotent Gauge Groups

 Groups of smooth maps from spheres to appropriate nilpotent Lie groups exhibit some peculiar properties of the unitary duals of infinite-dimensional groups. Received: 22 October 2000 / Accepted: 22 November 2002 Published online: 21 February 2003 RID="⋆" ID="⋆" This research was supported in part by CONICET, FONCYT, CONICOR and UNC. Communicated by H. Araki     

Localization for Random Unitary Operators

We consider unitary analogs of one-dimensional Anderson models on defined by the product U _ω=D _ω S where S is a deterministic unitary and D _ω is a diagonal matrix of i.i.d. random phases. The operator S is an absolutely continuous band matrix which depends on a parameter controlling the size of its off-diagonal elements. We prove that the spectrum of U _ω is pure point almost surely for all values of the parameter of S. We provide similar results for unitary operators defined on together with an application to orthogonal polynomials on the unit circle. We get almost sure localization for polynomials characterized by Verblunsky coefficients of constant modulus and correlated random phases Mathematics Subject Classification. 82B44, 42C05, 81Q05     

Unitary Positive-Energy Representations of Scalar Bilocal Quantum Fields

The superselection sectors of two classes of scalar bilocal quantum fields in D ≥ 4 dimensions are explicitly determined by working out the constraints imposed by unitarity. The resulting classification in terms of the dual of the respective gauge groups U(N) and O(N) confirms the expectations based on general results obtained in the framework of local nets in algebraic quantum field theory, but the approach using standard Lie algebra methods rather than abstract duality theory is complementary. The result indicates that one does not lose interesting models if one postulates the absence of scalar fields of dimension D−2 in models with global conformal invariance. Another remarkable outcome is the observation that, with an appropriate choice of the Hamiltonian, a Lie algebra embedded into the associative algebra of observables completely fixes the representation theory.     

The Braid Group Representation of IRF Model

The braid group representations (BGRs) corresponding to IRF model are discussed by solving the spectral-independent Yang-Baxter Equation in the cases q = 2 and 3. The BGRB obtained here are constant matrices.     

Quantum Supergroups V. Braid Group Action

We construct a braid group action on quantum covering groups. We further use this action to construct a PBW basis for the positive half in finite type which is pairwise-orthogonal under the inner product. This braid group action is induced by operators on the integrable modules; however, these operators satisfy spin braid relations.     

Enhanced Gauge Symmetry and Braid Group Actions

 Enhanced gauge symmetry appears in Type II string theory (as well as F- and M-theory) compactified on Calabi–Yau manifolds containing exceptional divisors meeting in Dynkin configurations. It is shown that in many such cases, at enhanced symmetry points in moduli a braid group acts on the derived category of sheaves of the variety. This braid group covers the Weyl group of the enhanced symmetry algebra, which itself acts on the deformation space of the variety in a compatible way. Extensions of this result are given for nontrivial B-fields on K3 surfaces, explaining physical restrictions on the B-field, as well as for elliptic fibrations. The present point of view also gives new evidence for the enhanced gauge symmetry content in the case of a local A _2n -configuration in a threefold having global ℤ/2 monodromy. Received: 28 October 2002 / Accepted: 9 December 2002 Published online: 28 May 2003 Communicated by R.H. Dijkgraaf     

General Eight-Vertex Model and Braid Group Representation

The braid group representations (BGRs) corresponding to general eight-vertex model are obtained for the case in which the total spins are not conserved. A Yang-Baxterization scheme is applied to obtain from these BGRs.     

Dynamical Localization for Unitary Anderson Models

This paper establishes dynamical localization properties of certain families of unitary random operators on the d-dimensional lattice in various regimes. These operators are generalizations of one-dimensional physical models of quantum transport and draw their name from the analogy with the discrete Anderson model of solid state physics. They consist in a product of a deterministic unitary operator and a random unitary operator. The deterministic operator has a band structure, is absolutely continuous and plays the role of the discrete Laplacian. The random operator is diagonal with elements given by i.i.d. random phases distributed according to some absolutely continuous measure and plays the role of the random potential. In dimension one, these operators belong to the family of CMV-matrices in the theory of orthogonal polynomials on the unit circle. We implement the method of Aizenman-Molchanov to prove exponential decay of the fractional moments of the Green function for the unitary Anderson model in the following three regimes: In any dimension, throughout the spectrum at large disorder and near the band edges at arbitrary disorder and, in dimension one, throughout the spectrum at arbitrary disorder. We also prove that exponential decay of fractional moments of the Green function implies dynamical localization, which in turn implies spectral localization. These results complete the analogy with the self-adjoint case where dynamical localization is known to be true in the same three regimes.     

New Braid Group Representations of C3(D3) and C4(D4) and Their Correspondent Link Polynomials

The new braid group representations of C₃(D₃) and C₄(D₄) are obtained by solving the defining relations of braid groups directly. And by introducing the appropriate diagonal matrices h, the associated link polynomials are derived also.     

Baxter-Bazhanox Model,Frenkel-Moore Equation and the Braid Group

In this paper the three-dimensional vertex model is given, which is the duality of the threedimensional Baxter-Bazhanov (BE) model. The braid group corresponding to Frenkel-Moore equation is constructed and the transformations R, I are found. These maps act on the group and denote the rotations of the braids through the angles π about some special axes. The weight function of another three-dimensional .vertex model related the 3D laettice integrable model proposed by Boos, Mangazeev, Sergeev and Stroganov is presented also, which can be interpreted as the deformation of the vertex model corresponding to the BB model.     

Poisson Algebras of Block-Upper-Triangular Bilinear Forms and Braid Group Action

In this paper we study a quadratic Poisson algebra structure on the space of bilinear forms on ${\mathbb{C}^{N}}$ C N with the property that for any ${n, m \in \mathbb{N}}$ n , m ∈ N such that n m = N, the restriction of the Poisson algebra to the space of bilinear forms with a block-upper-triangular matrix composed from blocks of size ${m \times m}$ m × m is Poisson. We classify all central elements and characterise the Lie algebroid structure compatible with the Poisson algebra. We integrate this algebroid obtaining the corresponding groupoid of morphisms of block-upper-triangular bilinear forms. The groupoid elements automatically preserve the Poisson algebra. We then obtain the braid group action on the Poisson algebra as elementary generators within the groupoid. We discuss the affinisation and quantisation of this Poisson algebra, showing that in the case m = 1 the quantum affine algebra is the twisted q-Yangian for ${\mathfrak{o}_{n}}$ o n and for m = 2 is the twisted q-Yangian for ${(\mathfrak{sp}_{2n})}$ ( sp 2 n ) . We describe the quantum braid group action in these two examples and conjecture the form of this action for any m > 2. Finally, we give an R-matrix interpretation of our results and discuss the relation with Poisson–Lie groups.     

Fusion Rings of Loop Group Representations

We compute the fusion rings of positive energy representations of the loop groups of the simple, simply connected Lie groups.     

Braid Group Statistics Implies Scattering in Three-Dimensional Local Quantum Physics

It is shown that quantum fields for massive particles with braid group statistics (Plektons) in three-dimensional space-time cannot be free, in a quite elementary sense: They must exhibit elastic two-particle scattering into every solid angle, and at every energy. This also implies that for such particles there cannot be any operators localized in wedge regions which create only single particle states from the vacuum and which are well-behaved under the space-time translations (so-called temperate polarization- free generators). These results considerably strengthen an earlier “NoGo-theorem for ’free’ relativistic Anyons”.