Boundary terms of the Einstein-Hilbert action

Understand

The Einstein-Hilbert action for general relativity is not well posed in terms of the metric $g_{ab}$ as a dynamical variable.

• There have been many proposals to obtain an well posed action principle for general relativity, e.g., addition of the Gibbons-Hawking-York boundary term to the Einstein-Hilbert action.
• These boundary terms are dependent on what one fixes on the boundary and in particular on spacetime dimensions as well.
• Following recent works of Padmanabhan we will introduce two new variables to describe general relativity and the action principle with these new dynamical variables will turn out to be well posed.