Perimeter Institute describes bound state of a black hole and particles as a “gravitational atom”.
In a paper released by the Perimeter Institute for Theoretical Physics and Stanford University, researchers describe how astronomical black holes may bind surrounding particles to form a gravitational atom analogous to hydrogen, with the black hole acting as the nucleus and the surrounding particles forming a state similar to the electron cloud.
While the idea of a gravitational atom may sound novel, the principles underlying such a state where described in the 1960s by physicist Roger Penrose, wherein he showed that energy and angular momentum can be extracted from the surrounding region of black holes.
Before Penrose, in the 1950s physicist John Archibald Wheeler formulated a description of gravitational-electromagnetic objects known as geons, wherein electromagnetic energy can become so high that it curves back on itself due to gravitational interaction, forms a torus shaped black hole, and will actually appear nearly identical to an elementary subatomic particle (a solution producing ‘mass without mass’, no Higgs required).
In more recent times, beginning in the 1990s, physicist Nassim Haramein demonstrated how “gravitational atoms” (to use the parlance of the Perimeter Institute) in which protons are black holes, are the key to understanding the fundamental properties of matter as well as the action of quantum gravity (arising from the Planck-scale electromagnetic oscillations of the quantum vacuum) – unifying physics from the quantum to the cosmological scale.
The key insight of the recent paper is in realizing that astronomical black holes and the associated particle sphere surrounding them can be thought of as macroscopic atoms (the reciprocal statement being valid as well, in which atoms are tiny black holes). Indeed, in its recent announcement the Perimeter Institute begins by explaining how particles can essentially be any size:
“Particles can be huge,” explains Perimeter Institute Faculty member Asimina Arvanitaki, a theoretical particle physicist. “In fact, they can be larger than a room, or they can be as large as the universe.”
Modeling black holes as large atoms offers particular benefits to understanding key fundamental physical processes and dynamics, just as understanding atoms as small black holes does (see for instance the Schwarzschild Proton by Haramein). One such phenomenal outcome theorized to occur due to the gravitational binding of particles in the ergosphere (the surrounding frame-dragged region of black holes that results from the high gravity and spin producing a strong magnetogravitic effect) is an effect referred to as superradiance.
The effect is produced through the Penrose process, wherein energy and angular momentum is transferred from a black hole to a particle that enters the ergo-region around the event horizon. As the particle is gravitationally bound to the black hole, it forms any one of the wavefunction configurations similar to the electron orbitals around hydrogen, and hence is called a gravitational atom. As the wave-particle resonates within the ergosphere, it gains energy and angular momentum through the Penrose process, and the number of wavefunctions is amplified, i.e. particles are produced from the ergosphere of the blackhole. As the effect continues, the number of particles grows exponentially. This is referred to as superradiance (superradiance is observed in phenomenon such as Cherenkov radiation, which occurs when particles travel through a dielectric substance faster than the speed of light for that medium, producing a shockwave similar to supersonic phenomena in air).
It should be noted that in the report the researchers are referring specifically to a particle conjectured from quantum chromodynamics (QCD) of the Standard Model of particle physics, known as the QCD axion. Similar to the strong force, the QCD axion was invented ad hoc, to explain particular problems associated with the QCD model of the strong force. For instance, it was demonstrated by Gerard ‘t Hooft that because of the non-trivial vacuum structure strong interactions modeled by QCD would result in a large electric dipole moment for the neutron, which is not observed. To overcome this observational disagreement with the Standard Model, the QCD axion was introduced. Because of its theoretical properties, it is thought to be a good candidate for dark matter. Moreover, axions are theorized to be up to 15 kilometers in diameter – large enough to form a resonant wave with the ergosphere of a stellar black hole.
In superradiance, similar to spontaneous or stimulated photon emission by electrons in atoms (the latter resulting in lasing, and indeed there are superradiant lasers), the particle sphere around a black hole can oscillate between high energy and low energy orbitals. Here, Arvanitaki and her collaborators at Stanford University make an interesting hypothesis: the transition of the superradiant particles from a high orbital to a low orbital level should result in the emission of gravitons (quantum units of gravitational waves). Although gravitational waves are predicted from general relativity, they have yet to be directly detected. The Laser Interferometer Gravitational-Wave Observatory (LIGO) is searching now for the detection of primordial gravitational waves thought to be produced during the early phase (Planck era) of universe formation. The detection of gravity waves emitted by the superradiant process of gravitational black hole atoms could verify such states.
The theory is particularly interesting to the physicists at the Resonance Project Foundation, as it draws the close parallels between black holes and subatomic particles, such as the proton – showing that the similarity of a stellar mass black hole to an actual atom is very close indeed. Moreover, Haramein has described the formation of the atomic nucleus through quantum gravity (utilizing and unifying both quantum and relativistic properties), yet it has often been inquired how the model describes electrons and the electron orbitals of atoms. To this, Haramein has described the electron orbital as the ergosphere region of the black hole proton – a conclusion closely reminiscent with the above theory just released by researchers at the Perimeter Institute and Stanford University. Detection of these specific class of graviton emissions from black hole atoms could be a major empirical validation of Quantum Gravity and the Holographic Mass, a result we will await with great anticipation!
 Associated with an electromagnetic disturbance is a mass, the gravitational attraction of which under appropriate circumstances is capable of holding the disturbance together for a time long in comparison with the characteristic periods of the system. Such gravitational-electromagnetic entities, or “geons”; are analyzed via classical relativity theory.