Micro black hole

The Micro Black Hole ( English for "micro black hole") is a hypothetical , very small and light black hole .

In the mid-1970s, Roger Penrose suggested that black holes could also be created in the laboratory. There are theories that it is possible with the Large Hadron Collider (LHC), which went into operation on September 10, 2008, to create such black holes up to once per second. However, this requires the existence of additional compact space dimensions , which u. a. can be predicted by certain string theory models .

Such black holes would not be comparable to stellar black holes observed cosmologically. Their dimensions would be in the order of magnitude of elementary particles . Due to quantum effects ( Hawking radiation ), they would most likely annihilate again a very short time after their formation. The resulting elementary particles could be detected using particle detectors. According to the current state of research in this area, the particle showers ( jets ) produced would be more isotropically distributed than those produced when high-energy particles collide and should therefore be distinguished from them.

existence

All sizes are given in natural units .

According to the theory of black holes, the Schwarzschild radius and mass of a black hole are proportional to each other. Since it is assumed that below the Planck length quantum effects become dominant and stable black holes can no longer exist, there is also a lower limit for the mass of a black hole, which is about 1.22 × 10 ¹⁶ TeV / c ² (approximately 22 micrograms). This makes the generation of black holes in the laboratory seem impossible at first, since the maximum achievable energy in the largest particle accelerator (the LHC) is only a few TeV, i.e. 16 orders of magnitude too little.

This picture changes, however, if the theory is expanded to include so-called large extra dimensions . By this one understands compact additional spatial dimensions, whereby the "large" (well below one millimeter, even larger ones are already excluded by observations) is to be understood here in relation to other theories. Such additional dimensions arise naturally in very many models of string theory.

Under this condition, the law of gravitation changes as soon as one reaches energies which correspond to the radius of these extra dimensions. This also changes the mass scale above which the existence of black holes is possible:

{\ displaystyle m _ {\ text {p}} ^ {2} = m _ {\ text {f}} ^ {d + 2} R ^ {d}}

,

where is the Planck mass , the number of additional dimensions, the new fundamental mass scale, and the radius of the extra dimensions. ${\ displaystyle m _ {\ text {p}}}$ ${\ displaystyle d}$ ${\ displaystyle m _ {\ text {f}}}$ ${\ displaystyle R}$

If you take z. For example, if we assume that there are three additional dimensions with a radius of approx. 1 eV ⁻¹ , a mass of approx. 0.16 TeV results for the effective Planck mass and thus the possibility of producing black holes in the laboratory.

Another possibility is that black holes are created when cosmic rays collide with constituents of the earth's atmosphere . This has not yet been proven; progress may be made in the future through the Pierre Auger Observatory , which went into operation in 2004 .

Lifetime

The lifespan of such small black holes would presumably be very short because, like all black holes, they lose mass due to Hawking radiation and should eventually evaporate. Since the lifetime is proportional to the third power of the mass, there is an unobservable short lifetime for small black holes. They could potentially be detected by the elementary particles that are formed during their decay. However, it is not clear whether the Hawking effect can also be used in this case without modification, since its derivation is based on a negligible curvature of the event horizon , i.e. H. on "sufficiently" large mass.

It is assumed that the decay takes place in several phases. How this exactly works and whether there is a “relic” or whether the decay takes place completely is the subject of current research and has not been conclusively clarified. The LHC is currently investigating its possible formation and decay.

literature

Popular science

Ulf von Rauchhaupt : In other dimensions . Frankfurter Allgemeine Sonntagszeitung, May 14, 2006 pp. 74–75.
Bernard J. Carr, Steven B. Giddings: Black holes in the laboratory. In: Spectrum of Science. September 2005 p. 32.
Norbert Frischauf: Doomsday at CERN? Of energies, dimensions and black holes ... Online magazine The Orion .

Reviews

Steven B. Giddings: Black Holes at Accelerators . In: GW Gibbons, E. Paul S. Shellard (Ed.): The future of theoretical physics and cosmology: celebrating Stephen Hawking's 60th birthday . Cambridge University Press, 2003, ISBN 0-521-82081-2 , pp. 278-291 , arxiv : hep-th / 0205027 .
Panagiota Kanti: Black Holes in Theories with Large Extra Dimensions: a Review . In: Int.J.Mod.Phys. A19, 2004, p. 4899–4951 , doi : 10.1142 / S0217751X04018324 , arxiv : hep-ph / 0402168 .
Sabine Hossenfelder: What Black Holes Can Teach Us . 2004, arxiv : hep-ph / 0412265 .

Original literature (selection)

To the Hawking radiation:

Stephen Hawking : Particle creation by black holes . In: Communications in mathematical physics . tape 43 , no. 3 , 1975, p. 199–220 ( Open Access ).
Stephen Hawking: Breakdown of predictability in gravitational collapse . In: Physical Review D . tape 14 , no. 10 , 1976, p. 2460-2473 , doi : 10.1103 / PhysRevD.14.2460 .

For possible production in accelerators:

Ignatios Antoniadis , Nima Arkani-Hamed , Savas Dimopoulos , Gia Dwali : New dimensions at a millimeter to a fermi and superstrings at a TeV . In: Physics Letters B . tape 436 , no. 3–4 , 1998, pp. 257-263 , doi : 10.1016 / S0370-2693 (98) 00860-0 , arxiv : hep-ph / 9804398 .
Roberto Casadio, Benjamin Harms: Black hole evaporation and large extra dimensions . In: Physics Letters B . tape 487 , no. 3–4 , 2000, pp. 209-214 , doi : 10.1016 / S0370-2693 (00) 00840-6 , arxiv : hep-th / 0004004 .
Savas Dimopoulos, Greg Landsberg: Black holes at the large hadron collider . In: Physical Review Letters . tape 87 , no. 16 , 2001, p. 161602 , doi : 10.1103 / PhysRevLett.87.161602 , arxiv : hep-ph / 0106295 .

On the possible production by cosmic rays:

Jonathan L. Feng, Alfred D. Shapere: Black hole production by cosmic rays . In: Physical Review Letters . tape 88 , no. 2 , 2001, p. 21303 , doi : 10.1103 / PhysRevLett.88.021303 , arxiv : hep-ph / 0109106 .

Individual evidence

^ First beam in the LHC - accelerating science . CERN Press Office, September 10, 2008 (press release).

[1] First beam in the LHC - accelerating science . CERN Press Office, September 10, 2008 (press release).