Constraints on Relic Magnetic Black Holes

Abstract

We present current direct and astrophysical limits on the cosmological abundance of black holes with extremal magnetic charge. Because they don't Hawking radiate, much lighter primordial black holes could exist today if they are extremal. The dominant constraints come from white dwarf destruction for intermediate masses, and intergalactic gas heating for heavier black holes. Extremal magnetic black holes may catalyze proton decay, and thus we derive robust limits -independent of the catalysis cross section -from the above as well as from white dwarf heating. We discuss other bounds such as those from neutron star heating, solar neutrino production, binary formation and annihilation into gamma rays, and magnetic field destruction. We note that stable magnetically charged black holes can assist in the formation of neutron star mass black holes.

Q-monopole-ball: a topological and nontopological soliton

“…Other model-dependent bounds on magnetically charged objects can be found in refs. [19,47,[76][77][78], though things like stopping power in materials may need to be recalculated to apply some of these bounds to QMBs (especially if the QMB radius is large). Additionally, magnetic monopoles could be detected via their effects as they pass through the atmosphere.…”

“…We have discussed how the Parker bound and direct monopole searches apply to QMBs. However, many more monopole search strategies exist [19,47,[76][77][78] or could be recast from similar searches [79][80][81]. Several of these depend on the stopping power of monopoles in various materials (the Sun, the Earth, interstellar gases, etc.).…”

The Weak Gravity Conjecture Requires the Existence of Exotic AdS Black Holes

“…We will discuss the case in which an asymptotically AdS 4 black hole rotates and is magnetically charged [38], since this case currently attracts considerable attention, from both the observational [39][40][41][42][43] (see [44,45] for reviews) and theoretical [46][47][48]37] points of view. The magnetic case is particularly interesting to us because such a black hole is expected to be, generically, approximately extremal [47], and extremal black holes are of course the ones of most interest in connection with the WGC 4 .…”

Merger rate of charged black holes from the two-body dynamical capture

“…This paramount and non-trivial theorem allows people to reduce all BH solutions to just three physical quantities. Compared to Schwarzschild BHs, charged BHs emit not only gravitational radiation but also electromagnetic radiation, and have attracted much attention [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Recently, assuming that the influence of BH spins can be neglected, Bozzola et al found that the charge-to-mass ratios of up to 0.3 are compatible with Binary BH merger event GW150914 [21].…”