sassa_nf

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https://en.wikipedia.org/wiki/Many-minds_interpretation

Nonetheless, it is not what we experience within physical reality[citation needed]

Curious, how many-worlds explains that awareness of a particular outcome of measurement gets associated with a particular outcome.

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From:

juan_gandhi

OMG. Does such logic exist that supports all this, I wonder.

From:

thedeemon

In MWI if we have a measurement with N possible outcomes we have N "worlds", each with a copy of all the observers. Since inside one "world" you cannot see or feel other "worlds" and your copies there, what you should observe in MWI is exactly "what we experience within physical reality": you just observe a single "classical" outcome, you don't and can't feel being in superposition, even though you are in a superposition.

Carroll explains all this stuff very well in Something Deeply Hidden.

From:

sassa_nf

I get the idea that I can't feel the other "copies" of the world. What I am confused about is how I end up feeling myself in one particular copy of it, and not the other - especially since that must have some relationship to the probabilities of outcomes.

From:

thedeemon

Anthropic principle, basically. Every particular copy of you was born to one day experience this particular outcome. There is no split event, all the worlds and copies always existed, in parallel. So every "you" experiences whatever there is in that particular world.

From:

thedeemon

How probabilities work in MWI and why Born rule holds is not obvious indeed, there have been multiple attempts to answer, and it doesn't look like a completely and satisfiably solved question.

But for me there is an even bigger unanswered question: how the heck we experience time in MWI? If we're parts of one big wave function that evolves in time, according to equations its evolution is just changes in amplitudes of different "worlds", these amplitudes are not visible from the inside, each "world" is static, it's just some particular state vector. When you raise your hand according to QM equations it's just the world with your hand down gets a lower amplitude and another "world", another state where the hand is up gets a higher amplitude. Amplitudes change, worlds don't. So if there is no collapse and there are all those worlds, each particular world doesn't evolve or change, only amplitudes assigned to them do. So sitting in one of them how come you can see your hand raise? It's like you subjectively move from one "world" to another.

I did ask Carroll about it and he couldn't answer.

From:

sassa_nf

I am not too sure what you mean by a state vector, when you associate it with a world.

The way I understand quantum states is that a state vector is really all possible outcomes, so "a world" then is just one component of that vector. So a state vector is all the worlds combined.

Eg in quantum computing a system of two qubits is a tensor product of the vectors for each qubit. So one qubit has two amplitudes - one for 1, one for 0 - and a system of two qubits has four amplitudes - for 11, 10, 01, 00. Each world then is one of those, 11, 10, ... No?

From:

thedeemon

Yes, I meant basis vectors. The total quantum state is a vector that can be represented as a linear combination (superposition) of basis vectors, each of them we can call a "world". Each of them represents a possible state too.