In the middle of December, a number of specialized scientific and popular resources exploded with headings such as: “Results of computer simulation confirm that our universe is a hologram”. For that, we should blame the editors of Nature News website who noticed two publications by Japanese theoretical physicists submitted to the ArXiv repository in November 2013.
This story began as early as the end of past century, when Stephen Hawking and Jacob Bekenstein showed that black holes are really not so black: they emit something, though at a very low level. Almost simultaneously, in 1973, Soviet scientists Yakov Zeldovich and Alexei Starobinsky, while solving relativistic equations of quantum mechanics for a special case of rotating black holes, came to the conclusion that they should emit particles in the course of substance absorption. In 1974, Stephen Hawking explained this effect by quantum fluctuations near the event horizon – which is, roughly speaking, the boundary of what we now call a black hole. The most interesting thing, however, is not even that but the fact that, looking at the spectral characteristics of Hawking radiation, physicists came to the conclusion of irreversible loss of information that falls into a black hole. However, not all physicists shared this opinion: this led to the famous bet of Thorne, Hawking, and Preskill in 1997, in which, incidentally, my supervisor, who collaborated with Kip Thorne’s group on a project for detection of gravitation-wave radiation, took part as well.
Why is this issue so important for physicists? The point is that, first, information is inextricably linked with entropy, the most important thermodynamic variable. Let me remind you that Planck deduced the formula of black hole radiation when he was solving a problem on entropy, this formula has become one of the foundations of quantum mechanics, and the above-mentioned Bekenstein also arrived to the conclusion on radiation of a black hole when trying to calculate its entropy. And, second, it turned out so that scientists found an area of extreme conditions, a singularity (which, to put it simply, is a lot of weight in a very small volume), in which the postulates of general relativity contradict the postulates of quantum mechanics, in particular, quantum determinism. At the same time, both theories are very well supported by experience, especially quantum mechanics, without which the modern development of technologies would be totally impossible. By looking for solutions to Hawking’s paradox, many scientists also hoped to move forward in creating a theory of quantum gravity. And third, most physical laws can be derived … from the equations that tie together information and entropy. For those who want to dive deeper into this subject, I recommend that you get acquainted with Seth Lloyd’s popular science book Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos, published this year, and find out that the slogan “information protection = protection of the Universe” is not only the wonderful motto of our company, but also a bona fide scientific statement.
In the same year, 1997, when Hawking, Thorne, and Preskill made their bet on the fate of information in the depths of the black hole, Argentinian physicist Juan Malsadena hypothesized that the general theory of relativity, quantum theory, and the superstring theory that was gaining popularity at this time may be associated by a transformation similar to a holographic one. And at the end of November this year, a group of Japanese theorists led by Yoshifumi Hyakutake submitted to ArXiv two articles at once in which they calculated the mass and energy of a black hole, the boundary of its event horizon, and the properties of particles passing through it — and the properties of Hawking radiation as well. In the first article, the researchers used the postulates of string theory, and in the second, they simulated the universe as a holographic image of a low-dimensional space in which there is no gravity. The calculation results of two articles are well consistent with each other — and postulate that the information in a black hole did not disappear irreversibly. This, however, Stephen Hawking himself admitted in 2004, when he admitted his defeat in a dispute with Preskill and Thorne.
The conclusions of Japanese theorists will still be subjected to a comprehensive review and discussion, but if they are correct, scientists would get another key to understanding how the world works. And we, another confirmation of our slogan that, by protecting data, we protect the universe!
My supervisor, by the way, won a bottle of cognac in that bet between Hawking, Thorne and Preskill.
Related Links:
http://en.wikipedia.org/wiki/Thorne%E2%80%93Hawking%E2%80%93Preskill_bet
http://en.wikipedia.org/wiki/Black_hole_information_paradox
http://en.wikipedia.org/wiki/Hawking_radiation
http://penningtonplanetarium.wordpress.com/2013/12/12/is-the-universe-just-a-projection/#more-1476
http://www.nature.com/news/simulations-back-up-theory-that-universe-is-a-hologram-1.14328