2025/08/25 by Kumar, Naman
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2508.18508
We develop extended black-hole thermodynamics on a Dvali--Gabadadze--Porrati (DGP) brane by promoting the brane tension \(σ\) to a thermodynamic variable within the extended Iyer--Wald framework. The brane tension acts as a localized vacuum energy with pressure \(Pσ≡ -σ\), yielding a new work term \(Vσ dPσ\) in the first law and the corresponding Smarr relation. For static, spherically symmetric black holes we show that the conjugate volume equals the geometric volume \(Vσ=\tfrac4π3rh3\); for stationary, axisymmetric solutions it admits a covariant, slice-independent definition and evaluates to \(Vσ=\tfrac4π3 (r+3+a2 r+)\). Working on the ghost-free normal branch, the brane is asymptotically flat with a single horizon, so the construction avoids de Sitter obstructions. Along a flat-brane path, asymptotic flatness is preserved by co-varying the bulk cosmological constant, and induced-gravity effects are suppressed by \(rh/rc\). These results establish a consistent flat-braneworld realization of black-hole chemistry in which brane tension provides the physically motivated pressure variable.