2,079 research outputs found

    Deformations of modified rr-matrices and cohomologies of related algebraic structures

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    Modified rr-matrices are solutions of the modified classical Yang-Baxter equation, introduced by Semenov-Tian-Shansky, and play important roles in mathematical physics. In this paper, first we introduce a cohomology theory for modified rr-matrices. Then we study three kinds of deformations of modified rr-matrices using the established cohomology theory, including algebraic deformations, geometric deformations and linear deformations. We give the differential graded Lie algebra that governs algebraic deformations of modified rr-matrices. For geometric deformations, we prove the rigidity theorem and study when is a neighborhood of a modified rr-matrix smooth in the space of all modified rr-matrix structures. In the study of trivial linear deformations, we introduce the notion of a Nijenhuis element for a modified rr-matrix. Finally, applications are given to study deformations of complement of the diagonal Lie algebra and compatible Poisson structures.Comment: 18 pages, to appear in JNC

    General mapping of one-dimensional non-Hermitian mosaic models to non-mosaic counterparts: Mobility edges and Lyapunov exponents

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    We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts. This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critical points of localization or Lyapunov exponents of localized states in the corresponding non-mosaic models have already been analytically solved. To demonstrate the validity of this mapping, we apply it to two non-Hermitian localization models: an Aubry-Andr\'e-like model with nonreciprocal hopping and complex quasiperiodic potentials, and the Ganeshan-Pixley-Das Sarma model with nonreciprocal hopping. We successfully obtain the mobility edges and Lyapunov exponents in their mosaic models. This general mapping may catalyze further studies on mobility edges, Lyapunov exponents, and other significant quantities pertaining to localization in non-Hermitian mosaic models.Comment: 9 pages, 2 figure
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