Hayward black hole heat engine efficiency in anti-de Sitter space

In this paper, we attempt to further study the heat engine efficiency for the regular black hole (BH) with an anti-de Sitter (AdS) background where the working material is the Hayward–AdS (HAdS) BH. In the extended phase space, we investigate the heat engine efficiency of the HAdS BH by defining the cosmological constant as the thermodynamic pressure P and deriving the mechanical work from the PdV terms. Then, we obtain the relation between the efficiency and the entropy/pressure and plot these function figures. Meanwhile, we compare the relation between the HAdS BH with that of the Bardeen–AdS (BAdS) BH, where it is found that the efficiency of the HAdS BH increases with increase in the magnetic charge q in contrast to that of the BAdS BH decrease with increase in the magnetic charge q. We found that the HAdS BH is more efficient than the BAdS BH, and guess that it is related to the BH structure.

Dirac’s Formalism for Time-Dependent Hamiltonian Systems in the Extended Phase Space

Dirac’s formalism for constrained systems is applied to the analysis of time-dependent Hamiltonians in the extended phase space. We show that the Lewis invariant is a reparametrization invariant, and we calculate the Feynman propagator using the extended phase space description. We show that the Feynman propagator’s quantum phase is given by the boundary term of the canonical transformation of the extended phase space. We propose a new canonical transformation within the extended phase space that leads to a Lewis invariant generalization, and we sketch some possible applications.