arXiv subjects

Boris Feigin

Publications and source records attributed to Boris Feigin.

49 records · Page 3Linked to original sources

arXiv1996

Quantum current operators (III): Commutative quantum current operators, semi-infinite construction and functional models

We construct a commutative current operator $\bar x^+(z)$ inside $U_q(\hat{\frak sl}(2))$. With this operator and the condition of quantum integrability on the quantum current of $U_q(\hat{\frak sl}(2))$, we derive the quantization of the semi-infinite construction of integrable modules of $\hat{\frak sl}(2)$ with the current operator $e(z)$ of $\hat{\frak sl}(2)$. The quantization of the functional models for $\hat{\frak sl}(2)$ are also given.

q-alg↗

arXiv1996

Difference equations of quantum current operators and quantum parafermion construction

For the current realization of the affine quantum groups, a simple comultiplication for the quantum current operators was given by Drinfeld. With this comultiplication, we prove that, for the integrable modules of $U_q(\hat {\frak sl}(2))$ of level $k+1$, $x^\pm(z)x^\pm(zq^{\pm 2}) \cdot\cdot\cdot x^\pm(zq^{\pm 2k})$ are vertex operators satisfying certain q-difference equations, and we derive the quantum parafermions of $U_q(\hat {\frak sl}(2))$.

q-alg↗

arXiv1996

Quantum Group Representations and Baxter Equation

In this paper we propose algebraic universal procedure for deriving "fusion rules" and Baxter equation for any integrable model with $U_q(\widehat{sl}_2)$ symmetry of Quantum Inverse Scattering Method. Universal Baxter Q- operator is got from the certain infinite dimensional representation called q-oscillator one of the Universal R- matrix for $U_q(\widehat{sl}_2)$ affine algebra (first proposed by V. Bazhanov, S.Lukyanov and A.Zamolodchikov for quantum KdV case). We also examine the algebraic properties of Q-operator.

hep-th↗

arXiv1995

Integrals of Motion and Quantum Groups

A homological construction of integrals of motion of the classical and quantum Toda field theories is given. Using this construction, we identify the integrals of motion with cohomology classes of certain complexes, which are modeled on the BGG resolutions of the associated Lie algebras and their quantum deformations. This way we prove that all classical integrals of motion can be quantized. For the Toda field theories associated to finite-dimensional Lie algebras, the algebra of integrals of motions is the corresponding W-algebra. For affine Toda field theories this algebra is a commutative subalgebra of a W-algebra; it consists of quantum KdV hamiltonians.

hep-th↗

arXiv1995

Quantum W-algebras and Elliptic Algebras

We define quantum W-algebras generalizing the results of Reshetikhin and the second author, and Shiraishi-Kubo-Awata-Odake. The quantum W-algebra associated to sl_N is an associative algebra depending on two parameters. For special values of parameters it becomes the ordinary W-algebra of sl_N, or the q-deformed classical W-algebra of sl_N. We construct free field realizations of the quantum W-algebras and the screening currents. We also point out some interesting elliptic structures arising in these algebras. In particular, we show that the screening currents satisfy elliptic analogues of the Drinfeld relations in U_q(n^).

q-alg↗

arXiv1994

Kac-Moody Groups and Integrability of Soliton Equations

A new approach to integrability of affine Toda field theories and closely related to them KdV hierarchies is proposed. The flows of a hierarchy are explicitly identified with infinitesimal action of the principal abelian subalgebra of the nilpotent part of the corresponding affine algebra on a homogeneous space. This is an extended version of the paper "Generalized KdV flows and nilpotent subgroups of affine Kac-Moody groups"; it has been accepted for publication in Inventiones Mathematicae.

hep-th↗

arXiv1994

On algebraic equations satisfied by hypergeometric correlators in WZW models. II

We give an explicit description of "bundles of conformal blocks" in Wess-Zumino-Witten models of Conformal field theory and prove that integral representations of Knizhnik-Zamolodchikov equations constructed earlier by the second and third authors are in fact sections of these bundles.

hep-th↗

arXiv1994

Gaudin Model, Bethe Ansatz and Critical Level

We propose a new method of diagonalization of hamiltonians of the Gaudin model associated to an arbitrary simple Lie algebra, which is based on Wakimoto modules over affine algebras at the critical level. We construct eigenvectors of these hamiltonians by restricting certain invariant functionals on tensor products of Wakimoto modules. In conformal field theory language, the eigenvectors are given by certain bosonic correlation functions. Analogues of Bethe ansatz equations naturally appear as Kac-Kazhdan type equations on the existence of certain singular vectors in Wakimoto modules. We use this construction to expalain a connection between Gaudin's model and correlation functions of WZNW models.

hep-th↗

arXiv1994

On bosonization of 2d conformal field theories

We show how bosonic (free field) representations for so-called degenerate conformal theories are built by singular vectors in Verma modules. Based on this construction, general expressions of conformal blocks are proposed. As an example we describe new modules for the $SL(2)$ Wess-Zumino -Witten model. They are, in fact, the simplest non-trivial modules in a full set of bosonized highest weight representations of $\hat {sl}_2$ algebra. The Verma and Wakimoto modules appear as boundary modules of this set. Our construction also yields a new kind of bosonization in 2d conformal field theories.

hep-th↗

arXiv1993

Fusion algebra at a rational level and cohomology of nilpotent subalgebras of sl_2

We define and calculate the fusion algebra of WZW model at a rational level by cohomological methods. As a byproduct we obtain a cohomological characterization of admissible representations of $\widehat{\gtsl}_{2}$.

hep-th↗

arXiv1993

Quasi-particles models for the representations of Lie algebras and geometry of flag manifold

We give a new interpretation and proof of the "quasi-particle" type character formulas for integrable representations of the simply-laced affine Kac-Moody algebras through a new "semi-infinite" construction of such representations. We compare formulas of this kind to other formulas obtained using the geometry of the corresponding flag manifold and in particular give a new proof to the Gordon type identities.

hep-th↗

arXiv1993

Integral Intertwining Operators and Complex Powers of Differential ($q-$Difference) Operators

We study a family of modules over Kac-Moody algebras realized in multi-valued functions on a flag manifold and find integral representations for intertwining operators acting on these modules. These intertwiners are related to some expressions involving complex powers of Lie algebra generators. When applied to affine Lie algebras, these expressions give integral formulas for correlation functions with values in not necessarily highest weight modules. We write related formulas out in an explicit form in the case of $\hat{\gtsl_{2}}$. The latter formulas admit q-deformation producing an integral representation of q-correlation functions. We also discuss a relation of complex powers of Lie algebra (quantum group) generators and Casimir operators to ($q-$)special functions.

hep-th↗

arXiv1993

Coinvariants of nilpotent subalgebras of the Virasoro algebra and partition identities

We prove that the dimensions of coinvariants of certain nilpotent subalgebras of the Virasoro algebra do not change under deformation in the case of irreducible representations of (2,2r+1) minimal models. We derive a combinatorial description of these representations and the Gordon identities from this result.

hep-th↗