Two routes to extract energy from a spinning black hole — BZ magnetic coupling and superradiant boson amplification — and one inescapable drain: Hawking evaporation. This workflow runs all three and sums the compute budget over the IMBH lifetime.
The Blandford-Znajek process couples magnetic field lines threading the event horizon to the hole's rotation, extracting rotational energy as a Poynting-flux jet. Power scales as P_BZ ∝ B² M² a². Mass and spin are also passed forward to Stages 2, 3, and 4 — they are the shared substrate parameters for all subsequent calculations.
Superradiance is the wave-field analogue of BZ: a massive bosonic field (axion, dark photon) resonates around the spinning hole when the superradiance condition ω < mΩ_H is met, exponentially growing a "cloud" that drains angular momentum. For an ultralight boson of mass μ, the gravitational fine-structure constant α = GMμ/ℏc³ determines the growth rate. M and spin are inherited from Stage 1.
Every black hole is losing mass to Hawking radiation — at a rate so slow for an IMBH that it's irrelevant on civilisational timescales, but crucial for comparing the substrate's total energy budget to any alternative. The evaporation time t_evap ∝ M³ means even 8,200 M☉ lasts ~10⁷⁹ years. M is inherited from Stage 1.
With BZ power (Stage 1) and evaporation lifetime (Stage 3) both known, this stage computes the total ops over the IMBH's life. The Landauer floor determines ops/joule; multiplied by Mc² gives the total budget. This is the ceiling on what the MTH civilisation can ever compute — and it is astronomical.
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