In a paper published in the journal New Astronomy, theoretical physicist Ovidiu Racorean suggests that X-ray photons emitted by accretion disks around rapidly spinning black holes — also known as Kerr black holes — have properties that make them ideal information carriers for quantum computing.
An artist’s impression of an accretion disk around a black hole. Image credit: XMM-Newton / ESA / NASA.
The term ‘black holes’ is widely known, but not everyone knows exactly what they are.
When stars come to the end of their lives, they can collapse in on themselves under their own weight, becoming denser and denser.
Some may collapse into a point with essentially no volume and infinite density, with a gravitational field that not even light can escape from: this is a black hole. If the star that forms it rotates, as most stars do, the black hole will also spin.
Material that gets close to a rotating black hole but does not fall into it will aggregate into a circular structure known as an accretion disk.
Powerful forces acting on accretion disks raise their temperature so they emit X-rays, which can act as carriers of quantum information.
The photons that make up the X-rays have two properties: polarization and orbital angular momentum.
Each of these can encode a qubit (quantum bit) of information, the standard information unit in quantum computing.
“Lab-based researchers already use beam splitters and prisms to entangle these properties in X-ray photons and process quantum information,” said Dr. Racorean, from Romania’s General Direction of Information Technology.
“It now seems that the curvature of spacetime around a black hole will play the same role as this apparatus.”
Thus far, however, this process is only a prediction.
The final proof will come when the properties of X-rays near Kerr black holes are observed, which could happen in the next decade.
“If we find that the X-ray polarization changes with distance from the black hole, with those in the central region being least polarized, we will have observed entangled states that can carry quantum information,” Dr. Racorean said.
“This topic may seem esoteric, but it could have practical applications. One day, we may even be able to use rotating black holes as quantum computers by sending X-ray photons on the right trajectory around these ghostly astronomical bodies.”
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Ovidiu Racorean. 2018. Creation of single-photon entangled states around rotating black holes. New Astronomy 59: 65-70; doi: 10.1016/j.newast.2017.09.001
This article is based on text provided by Elsevier.
