When Black Holes Can Call the Shots
When Black Holes Can Call the Shots
An international group of researchers, with the participation of Federico II University, is exploring the conditions under which a black hole could split in two
Black holes can merge. Under certain conditions, the reverse process—a black hole splitting into two—might also be possible.
A new study conducted by researchers at the University of Naples Federico II, the University of Southern Denmark, the CNRS, and Sorbonne Université examines these conditions. The work was selected bythe American Physical Society for its press outreach program.
For a typical non-rotating black hole described by Einstein’s general relativity, the splitting would reduce the total entropy, violating the second law of thermodynamics. The researchers are studying how this picture might change in more complex situations: in spacetimes with extra dimensions, in modified theories of gravity, and for black holes with event horizons deformed by interaction with a superfluid of subatomic particles.
The study’s title refers to a shape resembling a pair of pants: a black hole corresponds to the waist, while two black holes at a later time correspond to the legs. The shape thus represents a possible evolution over time.
By comparing the configurations before and after a hypothetical fragmentation, the authors examine when the process might be compatible with thermodynamics and kinematic constraints.
This work may contribute to our understanding of primordial black holes and black hole mergers. If sufficiently small fragments were to form, their subsequent Hawking evaporation could produce signals that could be detected by gamma-ray telescopes.
The authors of the study are Giacomo Cacciapaglia, Manuel Del Piano, Francesco Sannino, and Vania Vellucci.
Giacomo Cacciapaglia is a CNRS researcher at the Laboratoire de Physique Théorique et Hautes Énergies (LPTHE), a joint research unit of Sorbonne Université and CNRS in Paris. Manuel Del Piano and Vania Vellucci are affiliated with the ℏQTC at the University of Southern Denmark.
Francesco Sannino is a member of the “Ettore Pancini” Department of Physics at the University of Naples Federico II and is director of the Quantum Field Theory Center (ℏQTC), affiliated with the Department of Mathematics and Computer Science (IMADA) at the University of Southern Denmark. He is also affiliated with the Danish Institute for Advanced Study at the same university and is a visiting professor at Durham University.
The article, “When black holes admit pair-of-pants topologies,” has been accepted for publication in Physical Review D.
DOI: 10.1103/cx69-t466