# Is Hawking radiation valid for a microscopic black hole?

A black hole evaporates by Hawking radiation.
The computation of the evaporation time uses some approximations.

Question: Is the evaporation time valid for a microscopic black hole?

In particular, is it possible that at a given miscroscopic scale, the evaporation stops?
For example at a microscopic scale so that the mass of the black hole is the neutron mass.

Hawking radiation is indeed usually calculated as a semiclassical effect (classical gravitational field and quantum matter), which is invalid at high energy ($\langle T_{\mu\nu}\rangle >> 1$) and high fluctuations ($\langle T_{\mu\nu} T^{\mu\nu} \rangle - \langle T_{\mu\nu} \rangle \langle T^{\mu\nu}\rangle >>1$). Still, it is a result that is replicated in most quantum gravity theories, when the calculations are possible. So unless we are getting close to the Planck mass (not sure what happens there), a microscopic black hole should still radiate