In Section III
we generalize the quantum mechanics of Schwarzschild BHs to noncommutative phase space.
Consider now the hypothesis that these (primordial) wormholes are a constituent of dark matter. Chapline [50], Meszaros [51], and Hawking and Carr [48, 52, 53] investigated the formation of such BHs and discovered that, due to their non-relativistic and effectively collisionless nature, they might be viable candidates for dark matter.
These Planck-scale remnants together with Planck-scale wormholes created after Big Bang could form a component of dark matter at the Universe [55]. The stability of such objects and a possible resolution to the information paradox has been studied in references in [55].
https://www.pnas.org/doi/10.1073/pnas.2211215119
Not only does dark matter seem to be real, but it outweighs the visible universe—meaning stars, planets, nebulae, galaxies, and anything else made of ordinary atoms—by a factor of five
some researchers have become more open to the notion that dark matter consists of primordial black holes that emerged from the Big Bang
They point to three primary reasons for the shift: first, attempts to find WIMPs or the other hypothesized dark matter particles have come up empty; second, results from gravitational wave experiments looking for ripples in space-time are surprisingly consistent with the PBH idea.
And third, the next decade or two could bring observational evidence that either confirms the existence of PBH dark matter or rules it out.
Any PBH left today would have to exceed about 1017 grams: the mass of Mount Everest compressed into a black hole with a radius less than that of a hydrogen atom. The upshot is that PBH dark matter is still possible, but only if the black-hole masses are distributed very broadly, with very low numbers in any given value.
A breakthrough occurred in late 2017, when physicists Ping Gao and Daniel Jafferis, both then at Harvard University, and Aron Wall, then at the Institute for Advanced Study in Princeton, N.J., discovered a way to prop open wormholes with quantum entanglement—a kind of long-distance connection between quantum entities. The peculiar nature of entanglement allows it to provide the exotic ingredient needed for wormhole stability. And because entanglement is a standard feature of quantum physics, it is relatively easy to create. “It’s really a beautiful theoretical idea,” says Nabil Iqbal, a physicist at Durham University in England, who was not involved in the research. Though the method helps to stabilize wormholes, it can still deliver only microscopic ones. But this new approach has inspired a stream of work that uses the entanglement trick with different sorts of matter in the hopes of bigger, longer-lasting holes.
Physicist Juan Maldacena of the Institute for Advanced Study, who had suggested connections between wormholes and entanglement back in 2013, and his collaborator Alexey Milekhin of Princeton University have found a method that could produce large holes. The catch in their approach is that the mysterious dark matter that fills our universe must behave in a particular way, and we may not live in a universe anything like this.
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