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Euler’s Theorem and the Smarr Relation

The area of a charged rotating (Kerr) black hole is given by \begin{equation} \label{eqn:kerr-area-relation} A = 4\pi \left[ 2 M^2 + 2 (M^4 – L^2 – M^2 Q^2)^{1/2} – Q^2 \right] \end{equation} This relation can be inverted to express the mass $M$ as a function of charge $Q$, area $A$ and angular momentum $L$: \begin{equation}… Continue reading Euler’s Theorem and the Smarr Relation