Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Nuclear Physics B

“Generalized” algebraic Bethe ansatz, Gaudin-type models and Z-graded classical r-matrices

T. Skrypnyk

Published Sep 19, 2016• 5 citations
Publisher

Abstract

We consider quantum integrable systems associated with reductive Lie algebra g l ( n ) and Cartan-invariant non-skew-symmetric classical r -matrices. We show that under certain restrictions on the form of classical r -matrices “nested” or “hierarchical” Bethe ansatz usually based on a chain of subalgebras g l ( n ) ⊃ g l ( n − 1 ) ⊃ . . . ⊃ g l ( 1 ) is generalized onto the other chains or “hierarchies” of subalgebras. We show that among the r -matrices satisfying such the restrictions there are “twisted” or Z p -graded non-skew-symmetric classical r -matrices. We consider in detail example of the generalized Gaudin models with and without external magnetic field associated with Z p -graded non-skew-symmetric classical r -matrices and find the spectrum of the corresponding Gaudin-type hamiltonians using nested Bethe ansatz scheme and a chain of subalgebras g l ( n ) ⊃ g l ( n − n 1 ) ⊃ g l ( n − n 1 − n 2 ) ⊃ g l ( n − ( n 1 + . . . + n p − 1 ) ) , where n 1 + n 2 + . . . + n p = n .

DOI
10.1016/j.nuclphysb.2016.09.006

Related papers

Gaudin-type models, non-skew-symmetric classical r-matrices and nested Bethe ansatz

T. Skrypnyk

We consider quantum integrable systems associated with the Lie algebra gl(n) and Cartan-invariant non-dynamical non-skew-symmetric classical r-matrices. We describe the sub-class of Cartan-invariant non-skew-symmetric r-matrices for which exists the standard procedure of the nested Bethe ansatz associated with the chain of embeddings gl(n)⊃gl(n−1)⊃gl(n−2)⊃⋯⊃gl(1). We diagonalize the corresponding quantum integrable systems by its means. We illustrate the obtained results by the examples of the generalized Gaudin systems with and without external magnetic field associated with three classes of non-dynamical non-skew-symmetric classical r-matrices.

Nuclear Physics B•Dec 9, 2014•7 citations

Z 2 -graded classical r -matrices and algebraic Bethe ansatz: applications to integrable models of quantum optics and nuclear physics

T. Skrypnyk

Abstract We consider quantum integrable models based on the Lie algebra gl ( n ) and non-skew-symmetric classical r -matrices associated with Z 2 -gradings of gl ( n ) of the following type: gl ( n ) = gl ( n ) 0 ¯ + gl ( n ) 1 ¯ , where gl ( n ) 0 ¯ = gl ( n 1 ) ⊕ gl ( n − n 1 ) . Among the considered models are Gaudin-type models with an external magnetic field, used in nuclear physics to produce proton–neutron Bardeen–Cooper–Schrieer-type models, n -level many-mode Jaynes–Cummings–Dicke-type models of quantum optics, matrix generalization of Bose–Hubbard dimers, etc. We diagonalize the constructed models by means of the ‘generalized’ nested Bethe ansatz.

Journal of Physics A Mathematical and Theoretical•Aug 12, 2016•11 citations

Twisted rational r-matrices and algebraic Bethe ansatz: Application to generalized Gaudin and Richardson models

T. Skrypnyk, N. Manojlović

In the present paper we develop the algebraic Bethe ansatz approach to the case of non-skew-symmetric gl(2)⊗gl(2)-valued Cartan-non-invariant classical r-matrices with spectral parameters. We consider the two families of these r-matrices, namely, the two non-standard rational r-matrices twisted with the help of second order automorphisms and realize the algebraic Bethe ansatz method for them. We study physically important examples of the Gaudin-type and BCS-type systems associated with these r-matrices and obtain explicitly the Bethe vectors and the spectrum for the corresponding quantum hamiltonians in terms of solutions of Bethe equations.

Nuclear Physics B•Apr 29, 2021•9 citations

“Twisted” rational r-matrices and the algebraic Bethe ansatz: Applications to generalized Gaudin models, Bose–Hubbard dimers, and Jaynes–Cummings–Dicke-type models

T. Skrypnyk

We construct quantum integrable systems associated with the Lie algebra gl ( n ) and non-skew-symmetric “shifted and twisted” rational r-matrices. The obtained models include Gaudin-type models with and without an external magnetic field, n-level ( n −1)-mode Jaynes–Cummings–Dicke-type models in the Λ-configuration, a vector generalization of Bose–Hubbard dimers, etc. We diagonalize quantum Hamiltonians of the constructed integrable models using a nested Bethe ansatz.

Theoretical and Mathematical Physics•Oct 1, 2016•6 citations

Quantum integrable systems, non-skew-symmetric r-matrices and algebraic Bethe ansatz

T. Skrypnyk

We prove the integrability of the general quantum Hamiltonian systems governed by an arbitrary non-skew-symmetric, so(3)-valued, nondynamical classical r-matrix with spectral parameters. We consider the most interesting example of these quantum integrable systems, namely, the so(3) “generalized Gaudin systems” in detail. In the case of an arbitrary r-matrix which is “diagonal” in the sl(2) basis we calculate the spectrum and the eigenvalues of the corresponding Hamiltonians using the algebraic Bethe ansatz technique.

Journal of Mathematical Physics•Feb 1, 2007•33 citations

Non-skew-symmetric classicalr-matrices and integrable cases of the reduced BCS model

T. Skrypnyk

We consider generalized quantum Gaudin systems in an external magnetic field associated with non-skew-symmetric sl (2)-valued classical r -matrices. We calculate spectra of the generating function of the corresponding Hamiltonians using the algebraic Bethe ansatz. We apply these results to the construction of integrable fermionic Hamiltonians of a generalized BCS type. We investigate the special cases when the corresponding integrable Hamiltonians contain only a pairing interaction term and consider an example of such a situation associated with a special non-skew-symmetric r -matrix.

Journal of Physics A Mathematical and Theoretical•Nov 6, 2009•46 citations
We consider quantum integrable systems associated with reductive Lie algebra g l ( n ) and Cartan-invariant non-skew-symmetric classical r -matrices. We show that under certain restrictions on the form of classical r -matrices “nested” or “hierarchical” Bethe ansatz usually based on a chain of subalgebras g l ( n ) ⊃ g l ( n − 1 ) ⊃ . . . ⊃ g l ( 1 ) is generalized onto the other chains or “hierarchies” of subalgebras. We show that among the r -matrices satisfying such the restrictions there are “twisted” or Z p -graded non-skew-symmetric classical r -matrices. We consider in detail example of the generalized Gaudin models with and without external magnetic field associated with Z p -graded non-skew-symmetric classical r -matrices and find the spectrum of the corresponding Gaudin-type hamiltonians using nested Bethe ansatz scheme and a chain of subalgebras g l ( n ) ⊃ g l ( n − n 1 ) ⊃ g l ( n − n 1 − n 2 ) ⊃ g l ( n − ( n 1 + . . . + n p − 1 ) ) , where n 1 + n 2 + . . . + n p = n .
We consider quantum integrable systems associated with the Lie algebra gl(n) and Cartan-invariant non-dynamical non-skew-symmetric classical r-matrices. We describe the sub-class of Cartan-invariant non-skew-symmetric r-matrices for which exists the standard procedure of the nested Bethe ansatz associated with the chain of embeddings gl(n)⊃gl(n−1)⊃gl(n−2)⊃⋯⊃gl(1). We diagonalize the corresponding quantum integrable systems by its means. We illustrate the obtained results by the examples of the generalized Gaudin systems with and without external magnetic field associated with three classes of non-dynamical non-skew-symmetric classical r-matrices.
Abstract We consider quantum integrable models based on the Lie algebra gl ( n ) and non-skew-symmetric classical r -matrices associated with Z 2 -gradings of gl ( n ) of the following type: gl ( n ) = gl ( n ) 0 ¯ + gl ( n ) 1 ¯ , where gl ( n ) 0 ¯ = gl ( n 1 ) ⊕ gl ( n − n 1 ) . Among the considered models are Gaudin-type models with an external magnetic field, used in nuclear physics to produce proton–neutron Bardeen–Cooper–Schrieer-type models, n -level many-mode Jaynes–Cummings–Dicke-type models of quantum optics, matrix generalization of Bose–Hubbard dimers, etc. We diagonalize the constructed models by means of the ‘generalized’ nested Bethe ansatz.
In the present paper we develop the algebraic Bethe ansatz approach to the case of non-skew-symmetric gl(2)⊗gl(2)-valued Cartan-non-invariant classical r-matrices with spectral parameters. We consider the two families of these r-matrices, namely, the two non-standard rational r-matrices twisted with the help of second order automorphisms and realize the algebraic Bethe ansatz method for them. We study physically important examples of the Gaudin-type and BCS-type systems associated with these r-matrices and obtain explicitly the Bethe vectors and the spectrum for the corresponding quantum hamiltonians in terms of solutions of Bethe equations.
We prove the integrability of the general quantum Hamiltonian systems governed by an arbitrary non-skew-symmetric, so(3)-valued, nondynamical classical r-matrix with spectral parameters. We consider the most interesting example of these quantum integrable systems, namely, the so(3) “generalized Gaudin systems” in detail. In the case of an arbitrary r-matrix which is “diagonal” in the sl(2) basis we calculate the spectrum and the eigenvalues of the corresponding Hamiltonians using the algebraic Bethe ansatz technique.
We consider generalized quantum Gaudin systems in an external magnetic field associated with non-skew-symmetric sl (2)-valued classical r -matrices. We calculate spectra of the generating function of the corresponding Hamiltonians using the algebraic Bethe ansatz. We apply these results to the construction of integrable fermionic Hamiltonians of a generalized BCS type. We investigate the special cases when the corresponding integrable Hamiltonians contain only a pairing interaction term and consider an example of such a situation associated with a special non-skew-symmetric r -matrix.