Nonperturbative Isentropic Processes in AdS Black Holes with Nonlinear Electrodynamics

TL;DR

This paper investigates isentropic processes for charged matter in AdS black holes with nonlinear electrodynamics by analyzing classically forbidden absorption barriers and calculating the nonperturbative tunnelling probability via the Euclidean action $S_E$. Using four distinct NLED models (NED, ModMax, Euler–Heisenberg, Born–Infeld), it shows that the isentropic condition $E - q\Phi = 0$ cannot be satisfied classically, but quantum tunnelling can proceed with probability $\Gamma \sim e^{-2S_E}$, where $S_E$ is obtained numerically. Across the models, $S_E$ generally increases with the nonlinear parameter and horizon radius, while decreasing with the black hole charge, implying smaller, more highly charged black holes are more susceptible to tunnelling, though the Euler–Heisenberg case exhibits nontrivial, model-dependent nuances. The findings hint at a potential universality of nonperturbative effects in black hole spacetimes and reinforce the robustness of semiclassical entropy bounds while allowing for nonperturbative deviations relevant to entropy bounds and information loss considerations.

Abstract

We study the isentropic processes in a class of Anti de Sitter black holes coupled to non-linear electrodynamics. We demonstrate that such processes are classically forbidden but can proceed via quantum mechanical tunnelling. We compute the Euclidean action associated with the tunnelling process and analyze its dependence on the black hole charge, horizon radius, and the non-linear electrodynamics parameters characterizing each model. We find that the tunnelling probability is increasingly suppressed as the strength of the non-linearity is enhanced. We further find that smaller black holes exhibit a significantly higher tunnelling probability compared to larger ones, indicating a departure from classical behaviour. We conjecture that this behaviour may be universal across a broad class of black hole spacetimes. We discuss the implications of our results for entropy bounds and their potential relevance to the black hole information loss paradox.

Figures (8)

• Figure 1: Effective potential experienced by the charged test particle for an isentropic absorption by NED AdS black hole
• Figure 2: The plots presented above depict the Euclidean action associated with the isentropic absorption of a charged particle by NED-AdS black hole. Here we considered $m=0.0002$, $q=0.005$
• Figure 3: Effective potential experienced by the charged test particle for an isentropic absorption by ModMax AdS black hole
• Figure 4: The plots presented above depict the Euclidean action associated with the isentropic absorption of a charged particle by ModMax-AdS black hole. Here we considered $m=0.0002$, $q=0.005$
• Figure 5: Effective potential experienced by the charged test particle for an isentropic absorption by Euler-Heidenberg AdS black hole