Physicists have expressed a new argument why the Universe cannot be a computer simulation: gravitational anomalies

Artistic representation of the space-time distortion in the crystal



What is the chance that our universe is the result of a computer simulation? This idea has long been discussed by scientists and specialists, and they disagree. It is clear that our distant descendants will have almost unlimited computing resources and will be able to create virtual worlds like ours. Given the large number of such worlds, there are small chances that we were lucky to live in the real world, and not in the simulation. For example, Ilon Musk estimates our odds at 0.1%, and astrophysicist Neil Degrass Tyson - at 50%. In general, a moot point.



Now two theoretical physicists from Israel and Russia have put forward a new argument in favor of the fact that our world cannot be a computer simulation. Some properties of space-time are too difficult to calculate on a computer of any performance.



The idea that our world is a computer simulation was argued by the professor at Oxford University, Nick Bostrom, co-founder of the World Association of Transhumanists and director of the Institute for the Future of Humanity. In his 2003 article, he discusses the possibilities of posthuman civilization and the historical simulations that they will create:

Let us imagine the historians of the future who model various scenarios of historical development. These will not be today's simplified models. Taking into account the enormous computational possibilities that these historians will have, very detailed simulations can be at their disposal in which every building, every geographical detail, every personality will be distinguishable. And each of these individuals will be endowed with the same level of computing power, complexity, and intelligence as a living person. Like Agent Smith, they will be created on the basis of software, but they will also have human mental characteristics. Of course, they may never realize that they are a program. To create an accurate model, you will need to make the perception of modeled individuals indistinguishable from the perception of people living in the real world.



Like the inhabitants of the Matrix, these people will exist in the artificial world, considering it real. Unlike the scenario with the Matrix, these people will consist entirely of computer programs ...



These assumptions are very curious. Possessing sufficient computing power, post people can create models of historical personalities who will have a full-fledged consciousness and who will consider themselves to be biological people living in an earlier time ...



Now, in 2003, about six billion biological people live on the planet. It is even possible that in the posthuman epoch, trillions of computer-generated people will live in the 2003 modeled for them, convinced that they are of biological origin - exactly the same as you and me. The math here is as simple as two-and-two: the vast majority of these people are mistaken; they believe that they are flesh and blood, but in reality they are not. There is no reason to exclude our civilization from these calculations. Almost all the chances come down to the fact that we live in the model year 2003 and that our physical bodies are a computer illusion.

Although all this is more like a thought experiment, the theoretical physicists are Zohar Ringel from the Center for Theoretical Physics at Rudolf Peierls University of Oxford and the Cancer Institute of Physics at the Hebrew University of Jerusalem, and Dmitry Kovrizhin from the Center for Theoretical Physics at Rudolf Peierls University at Oxford University and the Kurchatov National Research Center Institute ”put forward an argument that can prove the impossibility of creating a computer simulation like our world.



Ringel and Kovrizhin's key thesis of argumentation is that science does not know how to effectively simulate quantum effects, such as Hall's thermal conductivity ( the Riga-Leduc effect ). These are the so-called gravity anomalies, which are extremely difficult to observe directly. They reflect the distortion of space-time on a small scale and occur at sufficiently low temperatures in strong magnetic fields.



The Riga – Leduc thermomagnetic effect is that when a conductor is placed with a temperature gradient in a constant magnetic field perpendicular to the heat flux, a secondary temperature difference arises that is perpendicular to the magnetic field and heat flux.



The Monte-Carlo method is used to simulate quantum systems, but Ringel and Kovrizhin explain that gravitational anomalies are too complex a phenomenon that can ever be calculated. Roughly speaking, there are an infinite number of options, which makes it impossible to simulate using the Monte Carlo method due to the sign problem - the appearance of formally negative probabilities. According to most physicists, the problem of a sign is in principle unsolvable, and therefore a more or less complex non-equilibrium system cannot be calculated on a computer of any power in a finite time.



On the other hand, if the problem of the sign is solved, then Monte-Carlo simulation will theoretically become possible. But Ringel and Kovrizhin do not believe that such algorithms will appear in the future.



Scientists say that as the size of the simulation increases, the volume of necessary calculations will grow linearly or exponentially. In the case of exponential growth, the simulation of even a few hundred electrons will require a computer, which consists of a larger number of atoms than the Universe contains. Given the number of atoms in the universe (10 ⁸⁰ ), the creation of such a computer will become an incomprehensible and extremely incredible task, the authors write.



The term “computability” itself implies that a problem can be solved on a computer in a finite time using a finite amount of memory. In this sense, physicists have provided convincing arguments that our universe is still not computable. Although the debate among scientists probably will not stop there. It is possible that the creators of the simulation - our descendants or representatives of the alien mind - still found a way to circumvent the difficulties with the volume of calculations. In the end, scientists have proved only that the Universe is not computable for us using methods known to us. That is, we ourselves cannot do a similar simulation, but this does not mean that someone else can do such a simulation using approximations, changing the laws of physics in the simulation accordingly to simplify calculations and using quantum computers.



“Our work shows an intriguing connection between two seemingly unrelated areas: gravitational anomalies and computational complexity,” says Zohar Ringel, co-author of the scientific work. “It also shows that Hall’s thermal conductivity is a true quantum effect: one of those for which there are no analogues in classical physics.”



The scientific article was published on September 27, 2017 in the journal Science Advances (doi: 10.1126 / sciadv.1701758).