# How is the multiverse possible with the law of conservation of energy? [closed]

So I am not a physicist or have any background in physics but I enjoy thought experiments and thinking about the nature of our universe and I was thinking about the idea that we live in a multiverse where every possible decision is made in all of it's possible variations and I'm confused how this correlates with the law of conservation of energy.

Since it's easy to assume this type of multiverse branches out and grows at an exponential rate then shouldn't we observe a matching exponential loss of energy from our universe? Either the energy for this new universe had to be created from nothing which is in violation of the law or the energy from the previously existing universe would need to be divided between the newly created universe and the existing universe resulting in an observable loss of energy.

One thought that I have is that if time is in fact the 4th dimension then the future must be as concrete as the past (any point in time just an index along a dimensional axis) which would mean that the future is predetermined and all possible multiverses existed at the moment of the big bang and all of the energy was divided at that time. That would mean while we like the perceive that we made a decision and that decision branched out a new universe that perception is false. While in reality we always made that same "decision" and what we perceived to be a new universe always existed because our decision was predetermined and nothing was ever variable.

This all started with me doing a thought experiment into if we have free will or not which leads me here. Now I'm thinking that for everything to make sense 1) we don't have free will (not that it changes anything) 2) The multiverse exists as a immutable entity where every branch of the multiverse was created in all the infinite variations simultaneously.

## closed as unclear what you're asking by Qmechanic♦Aug 2 '18 at 5:21

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• The conventional energy conservation does not hold in GR. Consider e.g. inflation, your could ask your question there and will see where your assumption fails. – user178876 Aug 1 '18 at 23:53
• To reopen this post (v4), consider to specify (e.g. by including references/link) which multiverse theory you are talking about. If you meant the many worlds interpretation, then mention that. – Qmechanic Aug 2 '18 at 5:21

I suppose you are referring by this to the quantum multiverse, or many-worlds theory of quantum mechanics, not other multiverse theories and concepts like eternal inflation, since you talk about universes "splitting" or "branching".

This requires a clarification on what many worlds is - and what it is is nothing more or less than simply demanding the Schrodinger equation

$$\hat{H} [|\psi\rangle(t)] = [\hat{E} |\psi\rangle](t)$$

holds for the entire Universe, that is, that the whole Universe can/should be assigned a quantum state vector, and it satisfies this equation (Actually, it needs to be somewhat modified if we are to consider a relativistic Universe like the actual one, and this is where it's not sure the picture works because we don't yet know how to or if you should quantize gravity.), and that the collapse rule should be discarded or changed to a different ontological status.

When you do this, you end up with that all particles (or better, quantum fields) are in a superposition of each possible configuration of the Universe. In this sense, energy conservation is maintained, or not, if you prefer, in the same way it is in quantum mechanics before a measurement "collapses" a wave function, since that's effectively all we've removed: the collapse. The amplitude of energy states does not change because they are eigenstates of the Hamiltonian operator on the left, rather only their phase, which by interference changes the structure of the rest of the Universe, thus if you write the universal state as a sum of energy states, this result will obtain as well.

You should not think of the "separate universes" as constituting separate chunks of matter - rather, they are effectively the same thing as the two branches of an electron after it has been passed to a simple barrier-tunneling setup like this: