I Are the implications of MWI really this horrifying?

[PeroK]

Has anyone done an estimate of how many worlds there are now? If the universe is made of say,10^80 protons and electrons that have been interacting for about 14 billion years, what does the number come to? Isn't it unimaginably huge?

How many bifurcations does an individual human experience every day? Asking for a friend :)

I'm not sure there is a consensus on whether the number of branches is finite, countable or uncountable. I believe Everett himself postulated bifurcation into uncountably infinite branches.

 

[gmax137]

I believe Everett himself postulated bifurcation into uncountably infinite branches.

Well then in nearly all of them, the OP is not there. So the OP worrying about how things are going for him/her in these other worlds seems to miss the point. On the other hand, maybe there are some worlds where he/she is the king. And lives for ten thousand years. It's a glass half full thing.

 

[PeroK]

Well then in nearly all of them, the OP is not there. So the OP worrying about how things are going for him/her in these other worlds seems to miss the point. On the other hand, maybe there are some worlds where he/she is the king. And lives for ten thousand years. It's a glass half full thing.

Sure, especially if we believe that the origin of the galaxies is a series of quantum events in the early universe, then "most" branches do not have the Milky Way, Sun or Planet Earth, let alone an individual whose birth depended on a very specific set of macroscopic circumstances, which themselves were heavily dependent on quantum mechanical outcomes.

Taking about "being king" or "living for ten thousand years" may be missing the point. Even if there are such branches, then they must be statistically dominated by more normal outcomes.

That said, I'm not sure any of us has the capacity to make much sense of MWI from any sort of "human" perspective.

 

[stevendaryl]

I'm not sure there is a consensus on whether the number of branches is finite, countable or uncountable. I believe Everett himself postulated bifurcation into uncountably infinite branches.

Everett’s original paper on what came to be known as the “Many-Worlds Interpretation” didn’t talk about branching. It talked about the state of the rest of the world relative to the state of the observer.

 

[stevendaryl]

Everett’s original paper on what came to be known as the “Many-Worlds Interpretation” didn’t talk about branching. It talked about the state of the rest of the world relative to the state of the observer.

The original paper can be found here: http://jamesowenweatherall.com/SCPPRG/EverettHugh1957PhDThesis_BarrettComments.pdf

 

[hungrybear]

Once again excuse my ignorance but what does MWI say about quantum fluctuations in the vacuum, the random appearance and annihilation of pairs of quantum particles? I've struggled to find something for the general reader on this.

Are the fluctuations deterministic in MWI theory? Do they happen differently in different worlds? Or does MWI theory accept these as random?

 

[PeroK]

Once again excuse my ignorance but what does MWI say about quantum fluctuations in the vacuum, the random appearance and annihilation of pairs of quantum particles? I've struggled to find something for the general reader on this.

Are the fluctuations deterministic in MWI theory? Do they happen differently in different worlds? Or does MWI theory accept these as random?

Professor Neumaier has written several articles on the misconceptions and myth of quantum fluctuations.

https://www.physicsforums.com/insights/misconceptions-virtual-particles/

https://www.physicsforums.com/insights/vacuum-fluctuation-myth/

In short, the fluctuations are not themselves quantum events or interactions; they are a heuristic aid to calculating the amplitudes for real quantum events.

 

[PeterDonis]

what does MWI say about quantum fluctuations in the vacuum, the random appearance and annihilation of pairs of quantum particles?

This phenomenon (which, as @PeroK has noted, is often misdescribed and misunderstood) does not involve any measurements, so QM interpretations don't really say anything about it.

 

[Melbourne Guy]

Quantum theory was never relevant to classical computers until the time when tunneling become a problem.

I'm not sure that's true, @CoolMint. As I recall my comp sci history, transistor design - even the first one! - utilised QM. And I know that 'classical' computing is different to a quantum computer, but 'classical' does not mean QM wasn't / isn't needed for semiconductor design.