Bekenstein limits, (quantum) information theory and physics, dreams in the minds of gods etcâ€¦

Scott Aaronson, Your yearly dose of is-the-universe-a-simulation:

[â€¦] to whatever extent we believe the Bekenstein bound [â€¦] we believe that in quantum gravity, any bounded physical system (with a short-wavelength cutoff, yada yada) lives in a Hilbert space of a finite number of qubits, perhaps \(~10^69\) qubits per square meter of surface area. And as a corollary, if the cosmological constant is indeed constant (so that galaxies more than ~20 billion light years away are receding from us faster than light), then our entire observable universe can be described as a system of \(~10^122\) qubits. The qubits would in some sense be the fundamental reality, from which Lorentz-invariant spacetime and all the rest would need to be recovered as low-energy effective descriptions. [â€¦] this would mean that our observable universe could be simulated by a quantum computerâ€”or even for that matter by a classical computer, to high precision, using a mere \(~2^{10^122}\) time steps.

Huh.

Was the universe a hologram or a simulation? Was its boundary a program, or merely an interface? And if the latter, what sat on the other side watching it run? A few latter-day religions had predictably answered that question with the names of their favourite deities. BrĂĽks had never been entirely clear on what an omniscient being would need a computer for. Computation, after all, implied a problem not yet solved; insights not yet achieved. There was really only one sort of program for which foreknowledge of the outcome didnâ€™t diminish the point of the exercise. And BrĂĽks had never been able to find any religious orders which described God as a porn addict.

â€” Peter Watts,

Echopraxia.

- Egan, G. (1997). Distress. Nightshade Book.
- Watts, P. (2014). Echopraxia. [S.l.]: Tor.

Hsu, Stephen D. H. 2020. â€śDiscrete Hilbert Space, the Born Rule, and Quantum Gravity,â€ť July. http://arxiv.org/abs/2007.12938.