Novel Mechanism for Production of Planck Relics in Third Order Effective Field Theory

We present a novel mechanism for the formation of Planck-scale black hole remnants, or Planck relics. We use the third-order effective field theory corrections to the Schwarzschild geometry and Hawking temperature obtained in the literature to construct a modified evaporation law that departs significantly from Hawking's classical prediction at small masses. At a critical mass $M_{crit}$, the evaporation process comes to a halt: for $c_6 > 0$ the Hawking temperature remains finite while the leading-order mass-loss rate vanishes, whereas for $c_6 < 0$ the Hawking temperature itself drops to zero. In both cases the black hole mass approaches $M_{crit}$ only asymptotically, so that the evaporation time diverges and the objects become stable remnants. The corrected heat capacity exhibits qualitative departures from Hawking's result near the Planckian regime, with a sign change for $c_6 < 0$ and a shifted extremum for $c_6 > 0$. Our results show that cubic curvature corrections in effective field theory naturally give rise to black hole remnants without invoking ad hoc modifications to Hawking radiation.