Information about a black hole's insides might be imprinted in its gravitational field.What falls into a black hole, stays in a black hole, at least according to the laws of general relativity. But now, new research suggests that the material inside the black hole may leave a quantum imprint on the gravitational field outside of it.[1]

Figure 1. Black holes may grow quantum 'hair'.

Figure 1 is shows he expressed the fact that black holes have no visible features beyond their total mass, vortex and charge, with the phrase 'black holes have no hair'. This is called the hairless theorem.

After proving that black holes actually have these additional properties, Professor Hsu and co-authors named their discovery 'quantum hair from gravity'. its mean “black hole may grow quantum “hair”.

“Black holes have long been considered the perfect laboratory to study how to merge Einstein’s theory of general relativity with quantum mechanics,”.

“It was generally assumed within the scientific community that resolving this paradox would require a huge paradigm shift in physics, forcing the potential reformulation of either quantum mechanics or general relativity”.[2]

Hairy black holes

The notion that black holes have very few features to distinguish them from one another is called the no-hair theorem, a metaphor first popularized by physicist John Wheeler. The idea is that beyond mass, charge and spin, ”black holes don’t have distinguishing features — no hairstyle”, cut or color to tell them apart.

"The quantum gravitational force helps to detect the difference in the gravitational field." The memory of what went into the black hole is in the gravitational field.[3].

Calmet and his colleagues found that black holes may indeed have hair, albeit very subtle hair. The researchers work in quantum gravity, a field that seeks to understand gravitational forces through quantum mechanics. Using calculations developed over the past decade, the research team compared two theoretical stars that collapse into black holes of the same size, charge and spin, but which have a different initial chemical composition. The no-hair theorem would hold that it's impossible to tell whether the stars that made these two black holes were initially different from one another.

We found that quantum gravity enables us to find the difference in the gravitational field," Calmet said. "There's a memory in the gravitational field of what went into the black hole." [4].

References:

1. https://news.knowledia.com/CA/en/articles/black-holes-may-grow-quantum-hair-a4c5bf04ad4235253db98c2e6c65ff0fb426b885
2. http://www.sci-news.com/astronomy/quantum-hair-10641.html
3. https://vervetimes.com/black-holes-may-grow-quantum-hair/
4. https://www.livescience.com/black-hole-quantum-hair

Cite this article:

Gunasekar M (2022), Black Holes May Grow Quantum 'Hair', AnaTechMaz, pp.25