Light burden of memory: Constraining primordial black holes with high-energy neutrinos

Recent studies point out that quantum effects, referred to as ``memory burden,'' may slow down the evaporation of black holes. As a result, a population of light primordial black holes could potentially survive to the present day, thus contributing to the energy density of dark matter. In this work, we focus on light primordial black holes with masses ${M}_{\mathrm{PBH}}\ensuremath{\lesssim}{10}^{9}\text{ }\text{ }\mathrm{g}$ that, due to the memory burden effect, are currently evaporating, emitting high-energy particles, among which neutrinos, in the local Universe. Analyzing the latest IceCube data, we place novel constraints on the combined parameter space of primordial black holes and the memory burden effect. We also study the projected reach of future neutrino telescopes such as IceCube-Gen2 and GRAND. We find that the neutrino observations are crucial to probe scenarios with highly suppressed evaporation and light masses for primordial black holes.