Emergence of Species Scale Black Hole Horizons

Understand

The scale at which quantum gravity becomes manifest, the species scale $\Lambda_s$, has recently been argued to take values parametrically lower than the Planck scale.

• We use black holes of vanishing horizon area (small black holes) in effective field theories coupled to quantum gravity to shed light on how the three different physical manifestations of the species scale $\Lambda_s$ relate to each other.
• (i) Near the small black hole core, a scalar field runs to infinite distance in moduli space, a regime in which the Swampland Distance Conjecture predicts a tower of exponentially light states, which lower $\Lambda_s$.
• (ii) We integrate out modes in the tower and generate via Emergence a set of higher derivative corrections, showing that $\Lambda_s$ is the scale at which such terms become relevant.