Digital physics

Not to be confused with Computational physics.

Digital physics is a speculative idea suggesting that the universe can be conceived of as a vast, digital computation device, or as the output of a deterministic or probabilistic computer program.[1] The hypothesis that the universe is a digital computer was proposed by Konrad Zuse in his 1969 book Rechnender Raum[2] ("Calculating-space").[3] The term digital physics was coined in 1978 by Edward Fredkin,[4] who later came to prefer the term digital philosophy.[5] Fredkin encouraged the establishment of a digital physics group at what was then MIT's Laboratory for Computer Science, with Tommaso Toffoli and Norman Margolus playing key roles.

Digital physics posits that there exists, at least in principle, a program for a universal computer that computes the evolution of the universe. The computer could be, for example, a huge cellular automaton.[1][6] It is deeply connected to the concept of information theory, particularly the idea that the universe's fundamental building blocks might be bits of information rather than traditional particles or fields.

However, extant models of digital physics face challenges, particularly in reconciling with several continuous symmetries[7] in physical laws, e.g., rotational symmetry, translational symmetry, Lorentz symmetry, and the Lie group gauge invariance of Yang–Mills theories, all of which are central to current physical theories. Moreover, existing models of digital physics violate various well-established features of quantum physics, as they belong to a class of theories involving local hidden variables. These models have so far been disqualified experimentally by physicists using Bell's theorem.[8][9]

Despite these challenges, covariant discrete theories can be formulated that preserve the aforementioned symmetries.[10][11]

  1. ^ a b Schmidhuber, Jürgen (1997), Freksa, Christian; Jantzen, Matthias; Valk, Rüdiger (eds.), "A computer scientist's view of life, the universe, and everything", Foundations of Computer Science: Potential — Theory — Cognition, Lecture Notes in Computer Science, vol. 1337, Berlin, Heidelberg: Springer, pp. 201–208, arXiv:quant-ph/9904050, doi:10.1007/bfb0052088, ISBN 978-3-540-69640-7, S2CID 17830241, retrieved 2022-05-23
  2. ^ "Das Jahr des rechnenden Raums". blog.hnf.de (in German). Retrieved 2022-05-23.
  3. ^ Zuse, Konrad (1969). Rechnender Raum. Braunschweig: Springer Vieweg. ISBN 978-3-663-02723-2.
  4. ^ 6.895 Digital Physics Lecture Outline, MIT Course Catalog Listing, 1978 (PDF)
  5. ^ "Digital Philosophy | A New Way of Thinking About Physics". digitalphilosophy.org. Archived from the original on 2021-01-26.
  6. ^ Zuse, Konrad, 1967, Elektronische Datenverarbeitung vol 8., pages 336–344
  7. ^ Fritz, Tobias (June 2013). "Velocity polytopes of periodic graphs and a no-go theorem for digital physics". Discrete Mathematics. 313 (12): 1289–1301. arXiv:1109.1963. doi:10.1016/j.disc.2013.02.010.
  8. ^ Aaronson, Scott (2014). "Quantum randomness: if there's no predeterminism in quantum mechanics, can it output numbers that truly have no pattern?". American Scientist. 102 (4): 266–271. doi:10.1511/2014.109.266.
  9. ^ Jaeger, Gregg (2018). "Clockwork Rebooted: Is the Universe a Computer?". Quantum Foundations, Probability and Information. STEAM-H: Science, Technology, Engineering, Agriculture, Mathematics & Health. pp. 71–91. doi:10.1007/978-3-319-74971-6_8. ISBN 978-3-319-74970-9.
  10. ^ D'Ambrosio, Fabio (Feb 2019). "A Noether Theorem for discrete Covariant Mechanics" (PDF). arXiv:1902.08997.
  11. ^ Grimmer, Daniel (May 2022). "A Discrete Analog of General Covariance -- Part 2: Despite what you've heard, a perfectly Lorentzian lattice theory" (PDF). arXiv:2205.07701.