Gaudin models with irregular singularities

We introduce a class of quantum integrable systems generalizing the Gaudin model. The corresponding algebras of quantum Hamiltonians are obtained as quotients of the center of the enveloping algebra of an affine Kac-Moody algebra at the critical level, extending the construction of higher Gaudin Hamiltonians from B. Feigin et al. (1994) [17] to the case of non-highest weight representations of affine algebras. We show that these algebras are isomorphic to algebras of functions on the spaces of opers on P¹ with regular as well as irregular singularities at finitely many points. We construct eigenvectors of these Hamiltonians, using Wakimoto modules of critical level, and show that their spectra on finite-dimensional representations are given by opers with trivial monodromy. We also comment on the connection between the generalized Gaudin models and the geometric Langlands correspondence with ramification.     

The argument shift method and the Gaudin model

We construct a family of maximal commutative subalgebras in the tensor product of n copies of the universal enveloping algebra U ( ) of a semisimple Lie algebra . This family is parameterized by finite sequences μ, z ₁, ..., z _n , where μ ∈ ^* and z _i ∈ ℂ. The construction presented here generalizes the famous construction of the higher Gaudin Hamiltonians due to Feigin, Frenkel, and Reshetikhin. For n = 1, the corresponding commutative subalgebras in the Poisson algebra S( ) were obtained by Mishchenko and Fomenko with the help of the argument shift method. For commutative algebras of our family, we establish a connection between their representations in the tensor products of finite-dimensional -modules and the Gaudin model. __________ Translated from Funktsional’nyi Analiz i Ego Prilozheniya, Vol. 40, No. 3, pp. 30–43, 2006 Original Russian Text Copyright ? by L. G. Rybnikov     

Composition factors of the kac module for the lie superalgebras sl(3/3) and sl(r/r)

The central results of this article are two theorems on G _ō and G primitivity on relative level 1 of the Kac module ?(?) for the Lie superal-gebra G = sl(m/n). These theorems are combined with Kac module homomorphisms in order to prove a conjecture by Hughes et al. [HKV] on the number of composition factors of the Kac module for 3- and r- fold atypical highest weights of sl(3/3) and sl(rZ/r) respectively. Our theorems on G _ō and G primitivity are general in nature and therefore the results also include infinite-dimensional representations.     

The cartan-weyl basis for the yangian doubleDY (sl 3)

Using the analogues of Cartan-Weyl elements, we construct a realization of the Yangian Y (sl₃). This enables us to derive the explicit comultiplication formulas in Y (sl₃), the quantum double DY (sl₃) of the Yangian, and the universal R-matrix. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 111, No. 3, pp. 423–438, June, 1997.     

Eigenvalues of Bethe vectors in the Gaudin model

According to the Feigin–Frenkel–Reshetikhin theorem, the eigenvalues of higher Gaudin Hamiltonians on Bethe vectors can be found using the center of an affine vertex algebra at the critical level. We recently calculated explicit Harish-Chandra images of the generators of the center in all classical types. Combining these results leads to explicit formulas for the eigenvalues of higher Gaudin Hamiltonians on Bethe vectors. The Harish-Chandra images can be interpreted as elements of classical W-algebras. By calculating classical limits of the corresponding screening operators, we elucidate a direct connection between the rings of q-characters and classical W-algebras.     

Bethe algebra and the algebra of functions on the space of differential operators of order two with polynomial kernel

We show that the algebra of functions on the scheme of monic linear second-order ordinary differential operators with prescribed n + 1 regular singular points, prescribed exponents at the singular points, and having the kernel consisting of polynomials only, is isomorphic to the Bethe algebra of the Gaudin model acting on the vector space Sing of singular vectors of weight Λ^(∞) in the tensor product of finite-dimensional polynomial -modules with highest weights .      

A character formula for infinite dimensional representations of the type i superalgebras sl(m/n) and c(2)

Infinite dimensional representations of Type I Lie superalgebra sl(m/n) for which the highest weight is singly or multiply and diagonally atypical are shown to have a character formula which is a modified version of the Bernstein-Leites character formula. This formula is also shown to be valid for all infinite dimensional representations of the Lie superalgebra C(2) classified according to the atypicality type of the highest weight A     

sl(3,κ)正则幂零表示投射模的Lowey序列

基域k是特征为5的代数闭域,李代数g=sl(3,k).当p-特征函数χ为正则幂零且具有标准Levi型时,本文得到了g的主不可分解模的Lowey序列及其单模自扩张的维数.     

The Harish-Chandra theorem for the quantum algebrau q (sl (3))

A basis of a quantum universal enveloping algebraU is constructed; the following theorem is proved with the help of this basis: For any nonzero element U, there exists a finite-dimensional representation such that(u) 0.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 45 No. 3, pp. 436–439, March, 1993.     

Expansion of automorphic functions on sl3(C>/SU<3)

One constructs the expansion for automorphic functions on SL₃,()/SU(3) using the method presented by the author in a previous paper [Zap. Nauch. Sem. Leningr. Otd. Mat. Inst.,116, 119–141 (1982)].Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 125, pp. 144–153, 1983.     

Defect basis property of the eigenvectors of a selfadjoint operator-valued function and formula for defect

A continuous selfadjoint operator-valued functionA(x) is considered. Possible changes of dimension of the positive partA ₊(t) are investigated ast transverses through some Fredholm eigenvalue ₀ . Some results on defect basis property are obtained, and the formula for the defect is proved. Both holomorphic and non-holomorphic cases are considered.     

Applications of the Kuznetsov formula on GL(3)

We develop a fairly explicit Kuznetsov formula on GL(3) and discuss the analytic behavior of the test functions on both sides. Applications to Weyl’s law, exceptional eigenvalues, a large sieve and L-functions are given.     

The Selberg trace formula for SL(3,Z)

In this article the first step toward the generalization of the Selberg trace formula to the case of a rank 2 symmetric space S and a discrete group for which the fundamental region \S goes to infinity nontrivially appears. For S we use the space SL(3,)/SO(3) and for we use SL(3,). The fundamental results are Theorems 9 and 10, in which is calculated the contribution to the matrix trace of the operator K which appears in the right side of the trace formula of the expression h()d^c(), where ^c() is the continuous part of the spectral measure of the quasiregular representation on the space IL₂(\S).Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 63, pp. 8–66, 1976.     

Choquet order for spectra of higher Lamé operators and orthogonal polynomials

We establish a hierarchy of weighted majorization relations for the singularities of generalized Lamé equations and the zeros of their Van Vleck and Heine–Stieltjes polynomials as well as for multiparameter spectral polynomials of higher Lamé operators. These relations translate into natural dilation and subordination properties in the Choquet order for certain probability measures associated with the aforementioned polynomials. As a consequence we obtain new inequalities for the moments and logarithmic potentials of the corresponding root-counting measures and their weak-^* limits in the semi-classical and various thermodynamic asymptotic regimes. We also prove analogous results for systems of orthogonal polynomials such as Jacobi polynomials.