The discussion centers around the number of parallel worlds in the context of the many-worlds interpretation (MWI) of quantum mechanics. Participants explore various perspectives on whether the number of these worlds is finite, countable, uncountable, or potentially infinite, considering implications from quantum theory and related concepts.
Participants do not reach a consensus on the number of parallel worlds, with multiple competing views remaining. Some advocate for a finite count based on quantum mechanics, while others suggest an uncountable infinity based on different interpretations of MWI.
Limitations include unresolved assumptions about the nature of quantum states, the definitions of "worlds," and the implications of different interpretations of quantum mechanics. The discussion also reflects varying understandings of how quantum theory interacts with classical concepts.
Dmitry67 said:different branches which don't interact.
MathematicalPhysicist said:Unaccountable.
2^null_aleph
The explanation is rather simple, if every bit of infomartion is decoded to 0 or 1 (nay or yay) then the number of world is the number of sequences of 0 and 1, which we know from set theory what it is.
Max Tegmark said:The answer is that there are only a finite number of possible states that a Hubble volume can have, according to quantum theory
...
Although classical physics allows an infinite number of possible states that a Hubble volume can be in, it's a profound and important fact that quantum physics allows only a finite number.
...
Let's first ignore the important complication of past history and ask how many physically distinct states N there are in a volume V. In classical physics, N is infinite (indeed uncountably infinite) as you say, since even specifying the position of a single particle requires infinitely many decimals. In quantum mechanics, however, N is finite: if the temperature never exceeds T, we of course have N < ln S, where S is the entropy of the thermal state with temperature T (I'm taking Bolzmann's constant k=1). Interestingly, the number of states appears to be finite even when taking general relativity into account, which is closely related to the holographic principle: the entropy is maximized if all the matter in V is in a single black hole, in which case, as you know, the Bekenstein-Hawking formula says that N is of order the surface area measured in Planck units. So yes, I see your reasoning, and find it quite striking that quantum mechanics, uncertainty principle and all, contrary to what one might expect, gives fewer states than classical physics. In the limit V->oo, quantum mechanics therefore gives a countable rather than uncountable infinity of states
Quantum physics tells you that before experimenting you have a probability for certain outcomes.Dragonfall said:I don't see how this is related to quantum physics, or the many-worlds interpretation.
yossell said:I didn't understand your reply. How are these strings of 0s and 1s being generated? Why does every outcome correspond to an infinite string of 0 and 1, and why does every infinite string of 0 and 1 correspond to an outcome? You need a 1-1 correspondence between the two to get the result.