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]
^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. ISBN978-3-319-74970-9.