# Many worlds, observer and Entropy

According to Everett-interpretation or many world interpretation of quantum mechanics, each decision an observer makes, the world splits into two parallel universes, let’s say an observer in some point in Spacetime is tests the Schrödinger’s cat experiment, in one branch of the universe the cat is alive, let’s call it A, and in the other branch of the universe the cat is dead and let’s call that branch B, now we have two branches, A and B, the each one separately doubles into two new branches or let’s say each one splits into two or maybe more branches as far as observers exist.

Now let’s say assume the observer A makes an observation, then the world including the observer splits into two branches, we call these two new observers A_1 for one of them and A_2 for the other one.

also, the observer B makes an observation and we get B_1 and B_2,

Then it goes on and on with more terms, does this splitting has an end or a limit?

Let’s assume in some point of Spacetime in one branch of the universe(or Multiverse), let’s arbitrarily call this branch B_2_e, let’s say in this branch for some arbitrary reason life get extinct and there is no observer left, then this branch (B_2_e) won’t split again, and for any time after that moment of extinction one can say this world is ended as far as we consider Existence as something that we can measure or have some effects on our Reality or something we can know about,

just like some Mathematical theories that we can prove it is not always true, even though, for a long time we believed they maybe True, they are True in several situations or as in our example, the existence of the world (B_2_e) was True for a long time, but not always.

If time is infinite or large enough, the Entropy gets high enough, and at some point, life can’t exist in any of these worlds, or as Entropy increases, at some point, there is not enough energy difference for planets, even stars to exist.

Now one can say that, when some world splits, then they continue splitting, and if we measure the Entropy of two distinct Universes, one can say they are not always Equal, the Entropy is not the same in both branches of the Universe or at least we can say they are not always Equal,

As in the Schrödinger’s Cat experiment, in one branch the Schrödinger’s cat dies, the Entropy is different from the wold with the cat alive, and the difference between them is the cat being alive or not, and obviously, they are two different worlds if we just want to measure Entropy.

Now we have many worlds with many Entropy states, which means as Entropy increases these worlds will end or they stop splitting because of the lack of observation, but they don’t do that altogether, because they have different Entropy, some Worlds end sooner than others.

In (Delayed choice quantum eraser) experiment one can see that in quantum mechanics photons can send massages backward in time, if that is True that means the following:

When the branches of the multiverse end in order, one branch will more likely end after all the other worlds, and when the observer in that last branch makes an observation, all the other worlds will collapse, just like the collapse of the wave-function in quantum mechanics.

Now can one say the we live in the “Best of all possible worlds” and all the possible worlds that could exist as we know from philosophers like Leibniz, these possible worlds don’t exist because they already collapsed and what we call our world the “best of all possible worlds” or sometimes the “path of least action” is just the path of the particle in the “Best of all possible worlds”?

Note: Sorry if you couldn’t understand my English, because I’m not a native or a good English speaker. If you didn’t understand any part let me try to explain it more, And sorry if it sounds naive, but in science all questions are allowed , , thank you.

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Demystifier
Gold Member
let’s say in this branch for some arbitrary reason life get extinct and there is no observer left, then this branch (B_2_e) won’t split again
That's wrong, according to the Everett's interpretation the splitting has nothing to do with life or consciousness. The splitting happens only due to decoherence governed by the Schrodinger equation.

PeroK