Black hole quantum mechanics in the presence of species

G. Dvali, C. Gomez, D. Lüst

    Research output: Contribution to journalArticlepeer-review


    Recently within the context of a microscopic quantum theory, the Black Hole's Quantum N-Portrait, it was shown that continuous global symmetries are compatible with quantum black hole physics. In the present paper we revise within the same framework the semi-classical black hole bound on the number of particle species Nspecies. We show that unlike the bound on global charge, the bound on species survives in the quantum picture and gives rise to a new fundamental length-scale, Lspecies = √(Nspecies) LP, beyond which the resolution of species identities is impossible. This finding nullifies the so-called species problem. This scale sets the size of the lightest quantum black hole in the theory, Planckion. A crucial difference between the gravitational and non-gravitational species emerges. For gravitational species, the lightest black holes are exactly at the scale of perturbative unitarity violation, which is a strong indication for self-UV-completion of gravity. However, non-gravitational species create a gap between the perturbative unitarity scale and the lightest black holes, which must be filled by some unitarity-restoring physics. Thus, self-UV-completion of gravity implies that the number of non-gravitational species must not exceed the gravitational ones.

    Original languageEnglish (US)
    Pages (from-to)768-778
    Number of pages11
    JournalFortschritte der Physik
    Issue number7-8
    StatePublished - Jul 1 2013

    ASJC Scopus subject areas

    • General Physics and Astronomy


    Dive into the research topics of 'Black hole quantum mechanics in the presence of species'. Together they form a unique fingerprint.

    Cite this