Bihamiltonian structure of the classical superstring in AdS_5 x S**5
Andrei Mikhailov
TL;DR
The paper establishes a bihamiltonian framework for the classical superstring in AdS_5 x S^5 by deriving a boost-invariant symplectic structure and decomposing the canonical Poisson bracket into three compatible brackets with distinct scaling. It shows how the boost-invariant bracket relates to a chiral WZW (Kirillov) bracket through Hamiltonian reduction and connects the monodromy matrix to integrability via Casimir functionals. A detailed analysis of the AdS_5 x S^5 current algebra psu(2,2|4) and its Z_4 grading underpins the construction, including gauge and dressing transformations and the handling of fermionic degrees of freedom. The work culminates in a geometric interpretation of the boost-invariant Poisson bracket for the bosonic sector, tying the algebraic bihamiltonian structure to the underlying differential-geometric data of the string worldsheet and its normal frames.
Abstract
We discuss the bihamiltonian structure of the Metsaev-Tseytlin superstring in AdS_5 x S**5. We explicitly write down the boost-invariant symplectic structure for the superstring in AdS_5 x S**5 and explain its relation to the standard (canonical) symplectic structure. We discuss the geometrical meaning of the boost-invariant symplectic structure for the bosonic string.
