BF gravity with Immirzi parameter and cosmological constant

Understand

The action principle of the BF type introduced by Capovilla, Montesinos, Prieto, and Rojas (CMPR) which describes general relativity with Immirzi parameter is modified in order to allow the inclusion of the cosmological constant.

• The resulting action principle is on the same footing as the original Plebanski action in the sense that the equations of motion coming from the new action principle are equivalent to the Holst action principle plus a cosmological constant without the need of imposing additional restrictions on the fields.
• We consider this result a relevant step towards the coupling of matter fields to gravity in the framework of the CMPR action principle.