Many Lives in Many Worlds | Hacker News Reader

Many Lives in Many Worlds

fermatslibrary.com

The interpretation I prefer: the universal quantum state evolves unitarily at all times, and there are no parallel universes. Problem solved. Parallel universes are — by definition — unfalsifiable, so the best theory then is the simplest one, and that is a theory with one universe.

For similar reasoning used in a somewhat different scenario, see also http://plato.stanford.edu/entries/spacetime-holearg/

>the universal quantum state evolves unitarily at all times

What does that mean in layman's terms? Is that basically the Copenhagen interpretation (which has its own issues)

It's not so obvious that a single universe is simpler.

See http://space.mit.edu/home/tegmark/PDF/multiverse_sciam.pdf and the excerpt quoted in https://en.wikipedia.org/wiki/Multiverse#Occam.27s_Razor

In the context of Many Worlds, a "universe" is an approximately classical wave function, where the degree of approximation is limited by the uncertainty principle.

Even if you start with an approximately classical wave function, it may evolve into a state where it is no longer approximately classical. However, it might now be equal to the sum of _two_ approximately classical wave functions. Ie, two "universes".

So, the universal wave function hasn't split, but the attempt to represent that wave function by approximately classical wave functions _has_ split.

> but the attempt to represent that wave function by approximately classical wave functions _has_ split.

Exactly. The problem is that people keep trying to view quantum physics through a classical lens.

Decoherence is simply the fact that a quantum state evolves to a point where it can no longer be mathematically represented as a tensor product state. I don't lose any sleep over that.

There's a BBC documentary about this, also created for the 50th anniversary, starring his son, who happens to be a semi-famous singer-songwriter with the band Eels:

http://eelstheband.com/parallel_worlds.php

It's available in full on Vimeo and embedded at the bottom of the above page.

Truly a terrifying hypothesis. Dearly hope it is not true.

As it predicts quantum immortality we will all find out if we wait long enough:https://en.m.wikipedia.org/wiki/Quantum_suicide_and_immortal...

Ehm. Did someone picked a photo at parallel universe? Never heard of such an event.

That text is impossible to read for me. It's all light grey on white and patchy.

Reads fine for me (Firefox under Ubuntu).

If your browser support the no page style you can use that. But what you see, is perhaps the effects of popup. It's on the lower right side, maybe pressing escape works. (it does on linux.

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