Digital physics

Not to be confused with Computational physics.

Digital physics is a speculative idea 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 by Edward Fredkin in 1978,^[4] who later came to prefer the term digital philosophy.^[5] Fredkin encouraged the creation of a digital physics group at what was then MIT's Laboratory for Computer Science, with Tommaso Toffoli and Norman Margolus as primary figures.

Digital physics suggests 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]

Extant models of digital physics are incompatible with the existence of several continuous characters of physical symmetries,^[7] e.g., rotational symmetry, translational symmetry, Lorentz symmetry, and the Lie group gauge invariance of Yang–Mills theories, all central to current physical theory. Moreover, extant models of digital physics violate various well-established features of quantum physics, belonging to the class of theories with local hidden variables that have so far been ruled out experimentally using Bell's theorem.^[8][9]

However, covariant discrete theories can be formulated that preserve the aforementioned symmetries.^[10][11]

See also

• Mathematical universe hypothesis
• It from bit
• Simulation hypothesis
• Weyl's tile argument
• Natura non facit saltus

References

1. 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, Berlin, Heidelberg: Springer, vol. 1337, 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. . 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". arXiv:1902.08997. {{cite journal}}: Cite journal requires |journal= (help)
11. Grimmer, Daniel (May 2022). "A Discrete Analog of General Covariance -- Part 2: Despite what you've heard, a perfectly Lorentzian lattice theory". arXiv:2205.07701. {{cite journal}}: Cite journal requires |journal= (help)

Further reading

• Robert Wright, "Did the Universe Just Happen?", Atlantic Monthly, April 1988 - Article discussing Fredkin and his digital physics ideas