Scott Aaronson - Is Reality Discrete or Continuous?

Are there discrete “pixels” of spacetime? Can we experimentally-confirm this?
The debate goes back to the ancient Greeks - the question has not been equivocally resolved ye, though with quantum mechanics, there are amplitudes (complex numbers) and there is an infinite amount of possible amplitudes (in a system that tries to model this should then have continuous parameters for these amplitudes) - before amplitudes (complex numbers) are observed - it's in a continuous state, then when it is observed it collapses into one of the finite possible discrete states that it could collapse into i.e. into either a complex amplitude representing either 1 or 0, a discrete state.. so in a sense it's continuous before observed then discrete afterwards. Also there can be quantum systems where there could be an infinite amount of possible outcomes i.e. a particle with a position live in an infinite dimensional state space (where you would need infinite complex numbers to characterize their state) - so if these systems were formally described in fundamental physics then our fundamental physics would be continuous - and then therefore nature would too - but evidence emerged from Jackob Bekenstien and Stephen Hawking that these continuous models cannot appear in our fundamental descriptions of nature - a quantum theory of gravity.. that a bounded system seems to only able to be describable from a finite amount of quantum bits (finite list of amplitudes or dimensions) - and furthermore the discovery of dark energy and that the universe is expanding at an exponential rate means that we can only receive signals that only appear a certain distance away from us.. if dark energy is a cosmological constant then the whole of the observable universe is a bounded system.. and if we agree with the Bekenstien bound principle, then any measurement ever made could only have a finite amount of possible outcomes - and in this local sense nature would then seem discrete - on the other hand before we make the observation it would be described by an infinite set of amplitudes that form a continuum.

#philosophy #physics #philosophyofphysics #philsci #science #quantum

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Видео Scott Aaronson - Is Reality Discrete or Continuous? канала Science, Technology & the Future