I was also really taken aback by this quote.

I have no idea who put it there, but I can assure you the actual paper contains no such nonsense.

I would have thought whoever writes the google tech blogs is more competent than bottom tier science journalists. But in this case I think it is more reasonable to assume malice, as the post is authored by the Google Quantum AI Lead, and makes more sense as hype-boosting buzzword bullshit than as an honest misunderstanding that was not caught during editing.

Everett interpretation simply asserts that quantum wavefunctions are real and there's no such thing as "wavefunction collapse". It's the simplest interpretation.

People call it "many worlds" because we can interact only with a tiny fraction of the wavefunction at a time, i.e. other "branches" which are practically out of reach might be considered "parallel universes".

But it would be more correct to say that it's just one universe which is much more complex than what it looks like to our eyes. Quantum computers are able to tap into this complexity. They make a more complete use of the universe we are in.

I'm upset they put this in because this is absolutely not the view of most quantum foundations researchers.

You don't even have to get to the point where you're reading a post off Scott Aaronson's blog[1] at all; his headline says "If you take nothing else from this blog: quantum computers won't solve hard problems instantly by just trying all solutions in parallel."

[1]: https://scottaaronson.blog/

In the same way people believe P != NP, most quantum computing people believe BQP != NP, and NP-complete problems will still take exponential time on quantum computers. But if we had access to arbitrary parallel universes then presumably that shouldn't be an issue.

The success on the random (quantum) circuit problem is really a valdiation of Feynman's idea, not Deutsch: classical computers need 2^n bits to simulate n qubits, so we will need quantum computers to efficiently simulate quantum phenomena.

I don't understand the jump from: classical algorithm takes time A -> quantum algorithm takes time B -> (A - B) must be borrowed from a parallel universe.

Maybe A wasn't the most efficient algorithm for this universe to begin with?

> It lends credence to the notion that quantum computation occurs in many parallel universes, in line with the idea that we live in a multiverse, a prediction first made by David Deutsch.

That's in line with a religious belief. One camp believes one thing, other believes something else, others refuse to participate and say "shut up and calculate". Nothing wrong with religious beliefs of course, it's just important to know that is what it is.

The Schrödinger equation inherently contains a multiverse. The disagreement is about whether the wave function described by the equation collapses to a single universe upon measurement (i.e. whether the equation stops holding upon measurement), or whether the different branches continue to exist (i.e. the equation continues to hold at all times), each with a different measurement outcome. Regardless, between measurements the different branches exist in parallel. It’s what allows quantum computation to be a thing.

I suspect the real issue is that Big Tech investors and executives (including Sundar Pichai) are utterly hopped up on sci-fi, and this sort of stuff convinces them to dedicate resources to quantum computing.

>Do quantum computing folks really think that we are borrowing capacity from other universes for these calculations?

Doesn't this also mean that other universes have civilizations that could potentially borrow capacity from our universe, and if so, what would that look like?

It's a perfectly legit interpretation of what's happening, and many physicists share the same opinion. Of course the big caveat is that you need to interfere those worlds so that they cancel out, which necessarily requires a lower algorithmic bound which prevents you from doing infinite amount of computation in an instant.

> Do quantum computing folks really think that we are borrowing capacity from other universes for these calculations?

Tangentially related, but there's a great Asimov book about this called The Gods Themselves (fiction).

This is a viable interpretation of quantum mechanics, but currently there is no way to scientifically falsify or confirm any particular interpretation. The boundary between philosophy and science is fuzzy at times, but this question is solidly on the side of philosophy.

That being said, I think the two most commonly preferred interpretations of quantum mechanics among physicists are 'Many Worlds' and 'I try not to think about it too hard.'

It doesn’t make sense to me because if we can borrow capacity to perform calculations then we can “borrow” an infinite amount of energy.

Well. If you study quantum physics and the folks who found it like Max Planck, they believed in "a conscious and intelligent non-visible living energy force .. . the matrix mind of all matter".

I don't know much about multiverse, but we need something external to explain the magic we uncover.

Energy and quantum mechanics are really cool but dense to get into. Like Planck, I suspect there's a link between consciousness and matter. I also think our energy doesn't cease to exist when our human carcass expires.

Yes this is deeply unserious tangent in supposedly landmark technology announcement.

The quantum computer idea was literally invented by David Deutsche to test the many universes theory of quantum physics.

So are we now concerned with the environment of another universe? Like climate activitist but for multiverses?

> It performed a computation in under five minutes that would take one of today’s fastest supercomputers 1025 or 10 septillion years. If you want to write it out, it’s 10,000,000,000,000,000,000,000,000 years.

If it's not, what would be your explanation for this significant improvement then?