## Abstract

Yang–Baxter type models are integrable deformations of integrable field theories, such as the principal chiral model on a Lie group G or σ-models on (semi-)symmetric spaces G/F. The deformation has the effect of breaking the global G-symmetry of the original model, replacing the associated set of conserved charges by ones whose Poisson brackets are those of the q-deformed Poisson–Hopf algebra Uq ( ) g . Working at the

Hamiltonian level, we show how this q-deformed Poisson algebra originates from a Poisson–Lie G-symmetry. The theory of Poisson–Lie groups and their actions on Poisson manifolds, in particular the formalism of the non-abelian moment map, is reviewed. For a coboundary Poisson–Lie group G, this non-abelian moment map must obey the Semenov-TianShansky bracket on the dual group G*, up to terms involving central quantities. When the latter vanish, we develop a general procedure linking this Poisson bracket to the defining relations of the Poisson–Hopf algebra

Uq ( ) g , including the q-Poisson–Serre relations. We consider reality conditions leading to q being either real or a phase. We determine the nonabelian moment map for Yang–Baxter type models. This enables to compute the corresponding action of G on the fields parametrising the phase space of these models.

Hamiltonian level, we show how this q-deformed Poisson algebra originates from a Poisson–Lie G-symmetry. The theory of Poisson–Lie groups and their actions on Poisson manifolds, in particular the formalism of the non-abelian moment map, is reviewed. For a coboundary Poisson–Lie group G, this non-abelian moment map must obey the Semenov-TianShansky bracket on the dual group G*, up to terms involving central quantities. When the latter vanish, we develop a general procedure linking this Poisson bracket to the defining relations of the Poisson–Hopf algebra

Uq ( ) g , including the q-Poisson–Serre relations. We consider reality conditions leading to q being either real or a phase. We determine the nonabelian moment map for Yang–Baxter type models. This enables to compute the corresponding action of G on the fields parametrising the phase space of these models.

Original language | English |
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Number of pages | 36 |

Journal | Journal of Physics A: Mathematical and Theoretical |

Volume | 49 |

Issue number | 41 |

DOIs | |

Publication status | Published - 20 Sept 2016 |

## Keywords

- sigma-models
- integrable field theories
- Poisson-Lie symmetries