Transition Matrix, Poisson Bracket for gravitational solitons in the dressing formalism

Abstract

The Hamiltonian methods of the theory of solitons are applied to gravisolitons in the dressing formalism. The Poisson bracket for the Lie-algebra valued one-form $A(\varsigma, \eta, \gamma)=\Psi_{,\gamma}\Psi^{-1}$, for gravisolitons in the dressing formalism, for a specific background solution, is defined and computed, agreeing with results previously obtained. A transition matrix ${\cal T}=A(\varsigma, \eta, \gamma) A^{-1}(\eta, \xi, -\gamma)$ for $A$ is defined relating $A$ at ingoing and outgoing light cones. It is proved that it satisfies equations familiar from integrable pde's with the role of time played by the null coordinate $\eta$. This is a new result mathematically, since there has not been a transition matrix for $A$ in the litterature, while physically it presents the possibility of obtaining integrals of motion (for appropriate boundary conditions), from the trace of the derivative with respect to the null coordinate $\eta$, of ${\cal T}$, in terms of classical relativity connections, since $A(\gamma = \pm 1)$ can be expressed in a simple way in terms of the classical Christoffel symbols. This may prove of use upon quantization since connections are fundamental variables of quantum gravity. The roles of $\eta$ and $\varsigma $ may be reversed to obtain integrals of motion for $\varsigma$, thus $\varsigma$ playing the role of time. This ties well with the two-time interpretation and approach already established before.