The Multiverse Hierarchy
| dc.creator | Tegmark, Max | |
| dc.date | 2009-05-08 | |
| dc.date.accessioned | 2026-07-07T13:13:05Z | |
| dc.date.available | 2026-07-07T13:13:05Z | |
| dc.description | I survey physics theories involving parallel universes, arguing that they form a natural four-level hierarchy of multiverses allowing progressively greater diversity. Level I: A generic prediction of inflation is an infinite ergodic universe, which contains Hubble volumes realizing all initial conditions -- including an identical copy of you about 10^(10^29)m away. Level II: In chaotic inflation, other thermalized regions may have different physical constants, dimensionality and particle content. Level III: In unitary quantum mechanics, other branches of the wavefunction add nothing qualitatively new, which is ironic given that this level has historically been the most controversial. Level IV: Other mathematical structures give different fundamental equations of physics. The key question is not whether parallel universes exist (Level I is the uncontroversial cosmological concordance model), but how many levels there are. I discuss how multiverse models can be falsified and argue that there is a severe "measure problem" that must be solved to make testable predictions at levels II-IV. | |
| dc.description | 15 pages, 6 figs | |
| dc.identifier | https://arxiv.org/abs/0905.1283 | |
| dc.identifier | http://arxiv.org/abs/0905.1283 | |
| dc.identifier | In "Universe or Multiverse?", B. Carr ed., Cambridge University Press (2007) | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/229777 | |
| dc.subject | Popular Physics | |
| dc.title | The Multiverse Hierarchy | |
| dc.type | text |