4 ms·

Are the claims about the shortest distance, maximum force, and shortest instant of time all undisputed? Makes the universe seem really discrete and simulation-y

by choxi 4y ago

Are the claims about the shortest distance, maximum force, and shortest instant of time all undisputed? Makes the universe seem really discrete and simulation-y.

krastanov 4y ago
They are a bit misrepresented. Think of most of them as "we know today's theory of physics breaks beyond these parameter regimes". There is no "minimal distance", rather there is "distance at which our math model does not work". No need to assume that things go discrete at that distance. There are some that are in a different style though: v<c is a fundamental postulate (stated in a very cluncky way).
- bmacho 4y ago
  > There is no "minimal distance", rather there is "distance at which our math model does not work". The paper is talking about an other type of minimum distance: minimum measurable distance. It predicts it to be 2*planck time (pg.7): Combining the experimental limits on speed v, force F and action W using the general relation for energy E = F vt = W/t leads to a limit on measurements of time t given by t ≥ √4G~/c5. (10) The five principles thus eliminate instants of time and introduce a minimum time interval, given by √4G~/c5 ≈ 1.1 · 10−43 s, twice the Planck time.
meroes 4y ago
I think not for distance and time. I’m not a physicist but Nima Arkani-Hamed phrases the minimal distance measurable as a physical process limited by QM and GR effects. To probe smaller and smaller distances one needs more and more energy, and past some minimum distance the energy becomes so great your experiment collapses into a black hole. That’s just what QM (small wavelength->high energy) and GR (force of gravity compared to the other forces, enough energy and gravity dominates) tell us. Since energy is related to time by a symmetry I think minimal time is implicated in the same way. A better interpretation than minimal discrete values of the universe is we are butting up against experimental limitations. An old concept that doesn’t necessarily mean the world is limited in the same we way are.

by choxi 4y ago

Are the claims about the shortest distance, maximum force, and shortest instant of time all undisputed? Makes the universe seem really discrete and simulation-y.

krastanov 4y ago

They are a bit misrepresented. Think of most of them as "we know today's theory of physics breaks beyond these parameter regimes". There is no "minimal distance", rather there is "distance at which our math model does not work". No need to assume that things go discrete at that distance. There are some that are in a different style though: v<c is a fundamental postulate (stated in a very cluncky way).

bmacho 4y ago
> There is no "minimal distance", rather there is "distance at which our math model does not work". The paper is talking about an other type of minimum distance: minimum measurable distance. It predicts it to be 2*planck time (pg.7): Combining the experimental limits on speed v, force F and action W using the general relation for energy E = F vt = W/t leads to a limit on measurements of time t given by t ≥ √4G~/c5. (10) The five principles thus eliminate instants of time and introduce a minimum time interval, given by √4G~/c5 ≈ 1.1 · 10−43 s, twice the Planck time.

meroes 4y ago

I think not for distance and time. I’m not a physicist but Nima Arkani-Hamed phrases the minimal distance measurable as a physical process limited by QM and GR effects. To probe smaller and smaller distances one needs more and more energy, and past some minimum distance the energy becomes so great your experiment collapses into a black hole. That’s just what QM (small wavelength->high energy) and GR (force of gravity compared to the other forces, enough energy and gravity dominates) tell us. Since energy is related to time by a symmetry I think minimal time is implicated in the same way. A better interpretation than minimal discrete values of the universe is we are butting up against experimental limitations. An old concept that doesn’t necessarily mean the world is limited in the same we way are.