from offensive_mango

[cosmolinguist]

1. Can quantum probability waves "uncollapse", whatever that might mean?

2. Can you observe a particular probability wave as not having collapsed?

3. Can a wave collapse a bit (say you know some particle is within such-and-such cubic centimetre), and later collapse even more (say to within such-and-such cubic millimetre)?

PASS IT ON!

Comments

[offensive-mango.livejournal.com]

OMG, it's so rad.

I got it from muffledsqueak, you know.

[cosmolinguist]

It is SO infectious. LOL.

[paninogirl.livejournal.com]

Is there some inside joke I'm missing? I don't get it...

[cosmolinguist]

Not really. offensive_mango's friend asked these questions in his/her journal (yeah, I looked, I'm curious!) in apparent seriousness. Her intention in then propagating it s a "meme" may be some kind of comment on how there are things in the world that are more interesting than what you had for breakfast or the fourth missed call on your phone or which seven songs you like right now. AT least, that's pretty much why I took it from her--I'd rather know the answers to any of these questions than to any of those. :-)

[ivana-duboise.livejournal.com]

Mint cream Oreos™

The Hub Coffee House Cafe

The Shins - Girl Inform Me
The Killers - Mr. Brightside
Le Tigre - Deceptacon
The 5, 6, 7, 8's - Woo Hoo
Dutch Dub - Dare To Dream
Pizzicato Five - Baby Love Child
The Faint - Worked Up So Sexual

[cosmolinguist]

I miss Oreos! And the mint creme ones are the best! I want Oreos now.

That "Woo Hoo" song used to be a guilty-pleasure favorite of mine (guilty because I do not like the band) but then it started being in ads for iPods or something and I had sufficient reason to not like it any more.

[ivana-duboise.livejournal.com]

Woo Hoo was also in Kill Bill Vol. 1. It's currently set as my ringtone. Deceptacon had probably been on my phone for three days; it was definately time to change it.

[cosmolinguist]

Send me some mint Oreos, would ya?

[ivana-duboise.livejournal.com]

What is your address … would ya?

[hexar-le-saipe.livejournal.com]

1. Can quantum probability waves "uncollapse", whatever that might mean?

No. Once the probability wave has collapsed, the end result is known and cannot subsequently be changed to a different outcome.

2. Can you observe a particular probability wave as not having collapsed?

If I understand what you mean by the question, no. Once observed (i.e. you peeked and found out the state of the wave) the end result is known.

3. Can a wave collapse a bit (say you know some particle is within such-and-such cubic centimetre), and later collapse even more (say to within such-and-such cubic millimetre)?

No. Once the first collapse has taken place, the final result for that probability wave is known. Any movement after that creates a new probability wave, seperate and independent from the original wave.

(If you haven't read it, I highly recommend The Dancing Wu Li Masters (http://en.wikipedia.org/wiki/The_Dancing_Wu_Li_Masters) which we found on the cutout rack at our local mall bookseller less than a month ago. It's a bit out of date with regard to string theory, but it gives a fascinating overview of pre-string quantum physics as it compares to eastern mystical systems.

[cosmolinguist]

Well, I stole these questions, partially as a joke or to prove another point, but I probably wouldn't have done so if they aren't also things that interest me. However, they're things that interest me about which I know next to nothing. So, if you'll indulge a dumb question or two...

First of all your answer for #3 I think I understand, and I should've thought of that.

And #2 sounds like what happens when Andrew says "I'm going to go see if seventeeen million billion trillion quid has been left in our letterbox" and I say "Hm, not very likely, is it?" and then he yells, "Sure, now it's not, because you had to go and say that and collapse the waveform!" Thus I doom him to poverty, several times a week.

As for #1, I don't suppose it counts (or matters) that, if I'm getting this right, as soon as you have made the observation about the particle, it goes back to having only a certain probability of being here or going this fast. That's just the new-wave-set-up-again thing like #3, isn't it?

And I haven't read that book; it's one I've seen several times because I hang out in the Popular Science section of bookstores, but something about the title or the picture on the cover or something put me off it. (Either that or I always run out of money before I run out of books I want, which is also true. But I'm going to see about geting myself a library card one of these days!) If a friend actually recommends it to me, well, that's another thing entirely! I like books on such subjects, and if they're a bit out-of-date, that's okay; so am I, and I can only handle so much new weird stuff at one time, anyway.

[hexar-le-saipe.livejournal.com]

And #2 sounds like what happens when Andrew says "I'm going to go see if seventeeen million billion trillion quid has been left in our letterbox" and I say "Hm, not very likely, is it?" and then he yells, "Sure, now it's not, because you had to go and say that and collapse the waveform!" Thus I doom him to poverty, several times a week.

And for the same reason, anytime I happen to be in the mood to waste a few drachma on lottery tickets (yes, I know it's a tax on people who are bad at math, it's also money that I would otherwise be spending on something stupid and worthless) I put off checking the numbers as long as possible... as long as I haven't actually looked at the results, there is still a chance that I have a winning ticket!

As for #1, I don't suppose it counts (or matters) that, if I'm getting this right, as soon as you have made the observation about the particle, it goes back to having only a certain probability of being here or going this fast. That's just the new-wave-set-up-again thing like #3, isn't it?

Exactly.

I had been hearing good things about The Dancing Wu Li Masters for a while... I certainly never would have looked into it based on the title. Since it ended up being about $5.00 (I think) for the hardback, I figured I'd take a chance on it. It does a fairly good (IMO) job of summarizing post-Newtonian physics. I also like that every chapter in the book is chapter 1.

[cosmolinguist]

I put off checking the numbers as long as possible... as long as I haven't actually looked at the results, there is still a chance that I have a winning ticket!

I do this about lots of things, especially ones that I fear are going to be bad. But evne when I'm anticipating things that I think are going to be good. People think it's weird that stuff in quantum physics isn't precisely true until (and unless) it's being observed; yet many of us live in precisely that manner, on occasion, in our macro-world...

[cosmolinguist]

Heh. Well, I don't know if I'd say fault, exactly--you didn't do anything wrong. :-) The internet is a great place to ask questions you barely understand, at least I've found it so.