7 research outputs found
Analytical Bethe Ansatz for open spin chains with soliton non preserving boundary conditions
We present an ``algebraic treatment'' of the analytical Bethe ansatz for open
spin chains with soliton non preserving (SNP) boundary conditions. For this
purpose, we introduce abstract monodromy and transfer matrices which provide an
algebraic framework for the analytical Bethe ansatz. It allows us to deal with
a generic gl(N) open SNP spin chain possessing on each site an arbitrary
representation. As a result, we obtain the Bethe equations in their full
generality. The classification of finite dimensional irreducible
representations for the twisted Yangians are directly linked to the calculation
of the transfer matrix eigenvalues.Comment: 1
W-superalgebras as truncation of super-Yangians
We show that some finite W-superalgebras based on gl(M|N) are truncation of
the super-Yangian Y(gl(M|N)). In the same way, we prove that finite
W-superalgebras based on osp(M|2n) are truncation of the twisted super-Yangians
Y(gl(M|2n))^{+}.
Using this homomorphism, we present these W-superalgebras in an R-matrix
formalism, and we classify their finite-dimensional irreducible
representations.Comment: Latex, 32 page
Weight bases of Gelfand-Tsetlin type for representations of classical Lie algebras
This paper completes a series devoted to explicit constructions of
finite-dimensional irreducible representations of the classical Lie algebras.
Here the case of odd orthogonal Lie algebras (of type B) is considered (two
previous papers dealt with C and D types). A weight basis for each
representation of the Lie algebra o(2n+1) is constructed. The basis vectors are
parametrized by Gelfand--Tsetlin-type patterns. Explicit formulas for the
matrix elements of generators of o(2n+1) in this basis are given. The
construction is based on the representation theory of the Yangians. A similar
approach is applied to the A type case where the well-known formulas due to
Gelfand and Tsetlin are reproduced.Comment: 29 pages, Late
Manin matrices and Talalaev's formula
We study special class of matrices with noncommutative entries and
demonstrate their various applications in integrable systems theory. They
appeared in Yu. Manin's works in 87-92 as linear homomorphisms between
polynomial rings; more explicitly they read: 1) elements in the same column
commute; 2) commutators of the cross terms are equal: (e.g. ). We claim
that such matrices behave almost as well as matrices with commutative elements.
Namely theorems of linear algebra (e.g., a natural definition of the
determinant, the Cayley-Hamilton theorem, the Newton identities and so on and
so forth) holds true for them.
On the other hand, we remark that such matrices are somewhat ubiquitous in
the theory of quantum integrability. For instance, Manin matrices (and their
q-analogs) include matrices satisfying the Yang-Baxter relation "RTT=TTR" and
the so--called Cartier-Foata matrices. Also, they enter Talalaev's
hep-th/0404153 remarkable formulas: ,
det(1-e^{-\p}T_{Yangian}(z)) for the "quantum spectral curve", etc. We show
that theorems of linear algebra, after being established for such matrices,
have various applications to quantum integrable systems and Lie algebras, e.g
in the construction of new generators in (and, in general,
in the construction of quantum conservation laws), in the
Knizhnik-Zamolodchikov equation, and in the problem of Wick ordering. We also
discuss applications to the separation of variables problem, new Capelli
identities and the Langlands correspondence.Comment: 40 pages, V2: exposition reorganized, some proofs added, misprints
e.g. in Newton id-s fixed, normal ordering convention turned to standard one,
refs. adde