More quantum mind-bending

[ciphergoth]

I thought I knew that quantum mechanics was mindbending, but I never anticipated this:

[[Elitzur-Vaidman bomb-testing problem]]

which is now proposed as a new way to build quantum computers!

Comments

[purplerabbits.livejournal.com]

My brain hurts now!

Though I like this - "Clearly we can accumulate dud bombs by throwing the bombs, one by one, at a wall, and collecting the ones that do not explode." I have to point out that you can only do this repeatedly if they are very small bombs or it is a very large wall...

[wechsler.livejournal.com]

Sounds like the testing ground for Project Orion

[fluffymark]

That's my favourite quantum thought-experiment of all. I love the idea of counterfactuals - events that never happen, but that still cause later real events.

[mhw.livejournal.com]

It's not just a thought experiment. Zeilinger actually found a way to do something very close to that.

[http://users.livejournal.com/_lj_sucks_/]

I can't help thinking that reality ought not to let us get away with that.

[mhw.livejournal.com]

Oh yeah, thanks for reminding me of that! Anton Zeilinger actually implemented it some years back.

[babysimon]

I find it particularly appropriate that the page changed becawhile I was looking at it.

[mhw.livejournal.com]

You may find this to be a worthwhile read also.

[drdoug.livejournal.com]

Quantum effects like this are a great example of the universe being "not only queerer than we suppose, but queerer than we *can* suppose", to use Haldane's phrase.

People Just Don't Get It - understandably so since it's bonkers.

For example, I recently came across the publisher's reading group guide for Saturday by Ian McEwan, which includes this question:

3. When Henry hears about the cargo plane's safe landing, McEwan observes, "Schrödinger's cat was alive after all." How does Schrödinger's thought-experiment, allowing two outcomes to co-exist during a period of uncertainty, apply to Henry's daily life? How does it express the nature of human thought during times of anxiety?

Quantum superpositions and Schrödinger's cat is nothing to do with that sort of mundane, every-day uncertainty, where there is a definite answer but you just don't know what it is. It's way, way weirder than that. It's not that you don't know whether the cat's alive or dead: the cat is literally, actually, both alive and dead simultaneously. Which is obviously impossible.

more detail?

[cyphunk.livejournal.com]

do you have any more information on how this would be used in quantum computing?

Re: more detail?

[cyphunk.livejournal.com]

I can see how this could be used for basic logic but I'm not quite familiar enough with the subject to vision an example structure for efficient use. In any case, whatever resources you have would be useful for learning more.