Massive gravity with Lorentz symmetry breaking: Black holes as heat engines

In extended phase space, a static black hole in massive gravity is studied as a holographic heat engine. In the massive gravity theory considered, the graviton gains a mass due to Lorentz symmetry breaking. Exact efficiency formula is obtained for a rectangle engine cycle for the black hole considered. The efficiency is computed by varying two parameters in the theory, the scalar charge Q and lambda. The efficiency is compared with the Carnot efficiency for the heat engine. It is observed that when Q and lambda are increased that the efficiency for the rectangle cycle increases. When compared to the Schwarzschild-AdS black hole, the efficiency for the rectangle cycle is larger for the massive gravity black hole.