  The entropy of generic non-extremal dyonic black holes in the STU model has
been shown to admit a remarkably universal form. The missing invariant in the
formula was recently identified by S\'arosi using the formalism of quantum
entanglement as well as a higher dimensional embedding of the U-duality group.
Here, we express the non-extremal black hole entropy in the STU model in terms
of U-duality covariant tensors. We then provide the extension to the most
general non-extremal black hole of ungauged $\mathcal N= 8$ supergravity using
$E_{7(7)}$ invariants. We also conjecture a generalization for ungauged
$\mathcal N = 2$ supergravity coupled to vector multiplets with arbitrary cubic
prepotential. The most general rotating dyonic black hole solution of the STU
model with all scalar moduli turned on is provided in an appendix.

High Energy Physics - Theory