Quantum black holes and the Higgs mechanism at the Planck scale

In this paper we present a suitably adjusted Higgs-like mechanism producing black holes at, and beyond, the Planck energy. Planckian objects are difficult to classify either as "particles", or as "black holes", since the Compton wavelength and the Schwarzschild radius are comparable. Due to this unavoidable ambiguity, we consider more appropriate a quantum field theoretical (QFT) approach rather than General Relativity (GR), which is known to break down as the Planck scale is approached. A posteriori, a connection between the two description can be established for masses large enough with respect to the Planck mass, though always describing black holes at the microscopic level. We adopt a QFT inspired by the Higgs mechanism, in the sense that a massive scalar field develops a non-trivial vacuum for m>\mu_{Pl}. Exictations around this vacuum are Planckian objects we name "black particles" to remark the ambiguous identity of these objects, as it has been mentioned above. A black particle eventually turns into a "quantum black hole" when the Schwarzschild radius becomes larger than its Compton wavelength. However, for m=\mu_{Pl} the scalar field is massless at the tree-level, but develops a non-trivial vacuum at one-loop through a Coleman-Weinberg mechanism. In this case, excitations describe Planck mass black particles.