The R = T model,^[1] also known as Jackiw–Teitelboim gravity (named after Roman Jackiw and Claudio Teitelboim), is a theory of gravity with dilaton coupling in one spatial and one time dimension. It should not be confused^[2][3] with the CGHS model or Liouville gravity. The action is given by

${\displaystyle S={\frac {1}{\kappa }}\int d^{2}x\,{\sqrt {-g}}\,\Phi \left(R-\Lambda \right)}$

The metric in this case is more amenable to analytical solutions than the general 3+1D case though a canonical reduction for the latter has recently been obtained.^[4] For example, in 1+1D, the metric for the case of two mutually interacting bodies can be solved exactly in terms of the Lambert W function, even with an additional electromagnetic field.

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