Let’s envision ourselves in the distant cosmic future, at a time when all matter in the universe is beginning to tear apart due to the rapid acceleration of space. In this environment, one would expect to only see some subatomic particles and rogue waves of energy. However, there are also some interesting objects that were born at the dawn of time and are only now fading away: black holes. Black holes have the interesting capability of radiating away information from their “surface” over time. This radiation is known as Hawking radiation (named after famous physicist Stephen Hawking). In flat space, particle pairs burst in and out of existence rapidly and randomly in space. They destroy themselves so quickly because they are in themselves violations of the laws of physics in that they can quickly produce negative energy or even just produce a positive value of energy out of absolutely nothing. However, because they destroy themselves so quickly, the universe doesn’t mind. Around a black hole, the story is different. Near the event horizon of a black hole, the tidal gravity is so strong that if a particle pair forms near this region of space, one particle from the pair is pulled inside the black hole, while the other particle is flung into space. Normally, these quantum particle pair fluctuations are virtual (meaning they don’t have enough energy to truly exist as a particle). However, the energy gained in the process of Hawking radiation converts it into a real particle. Another interesting feature of Hawking radiation is that the high energy particles that escape remain entangled with their particle pair. Entanglement is a quantum mechanical concept in which two particles (or systems of particles) are connected in such a way where if you know something about one particle/system, you immediately know another piece of information about the other particle/system. This connection can exist regardless of how far the two particles/systems are from one another.
Hawking radiation is a very slow process, one that takes trillions and trillions of years to complete. However, once the black hole does finish radiating all its information into space, the black hole that previously existed is said to have “evaporated”. In the distant future I previously mentioned, black holes are on the verge of completing their evaporation process. The radiation released from the black hole remains entangled with the “dying” black hole. As such, once enough of the Hawking radiation is released, I thought it might be interesting to use the “dying” black hole as a computer. In essence, this might be one of the most advanced computers possible. It forms a quantum mechanical network extending billions of light years. By the end of the universe, the black hole would have radiated enough bits of information to form an incredibly complex system of nodes, all linked to the original black hole. For any one still out there at the end of time, at least you can still do your math homework!