Comments on: Or did I just BLOW YOUR FUCKING MIND?!

Or did I just BLOW YOUR FUCKING MIND?!

jmhodges — Tue, 25 Apr 2006 16:09:40 -0800

We've talked about quantum computation a few times before, but how much do we really know? Metafilter, instruct thyself. Don't forget to learn some advanced probability and computational complexity (Scott Aaronson has more). Whoa, that's a lot o' learning, so let's so check out the much easier, and much cooler "sleeping puppy" experiment. I can only dream that will help break quantum mechanics' association with animal abuse. Then, there's the Free Will Theorem that just came out (some discussion on it) and another paper with a new look at an old problem. The latter describes another way of solving ye olde, super importanto Einstein-Podolsky-Rosen paradox using the relational interpretation of quantum mechanics (lots of discussion running around). Whew. We don't need the crackpot ramblings of What the #$*! Do We Know? when we've got real physics to keep us up at night. So, who wants to become a physicist? (t'Hooft has some thoughts for those who want to go theoretical.)

By: jmhodges

jmhodges — Tue, 25 Apr 2006 16:15:01 -0800

Crap, I forgot Scott's Quantum Computing for High School Students which is a nice introductory piece. Mea culpa.

By: rolypolyman

rolypolyman — Tue, 25 Apr 2006 16:17:31 -0800

I've had lots of trouble grasping quantum computing, and have been hoping in despair that someone will write a "Mr. T Teaches Quantum Computing" comic strip.

By: Baby_Balrog

Baby_Balrog — Tue, 25 Apr 2006 16:34:07 -0800

Holy cow that puppy article is awesome. And no poisoning of juvenile animals or anything. Excellent post.

By: Orange Goblin

Orange Goblin — Tue, 25 Apr 2006 16:51:00 -0800

Yeah, the puppy article is pretty cool. And the puppy is so cute!

By: delmoi

delmoi — Tue, 25 Apr 2006 17:02:42 -0800

Scott Arronson is a total dick, and much less intelegent then he thinks he is.

By: Osmanthus

Osmanthus — Tue, 25 Apr 2006 17:07:02 -0800

Once the spin of a particle is decided, how long does that decision remain true? Forever? [I'm not talking about the spin of the particle changing, only about the information about the measurement event] Currently our mindset is that once a decision is made, it is true for all time; maybe this is wrongheaded. Quantum erasure shows that quantum information of this sort can be erased as long as it is never leaked into the universe. Extending this idea, can macroscopic parts of the universe be erased? Perhaps the reason why measurements in these experiements always correlate is that when the information is brought together, conflicts are erased. I think that erasure doesnt need to imply a multiverse but only that time be two dimensional. How much do we know about time anyway? As a tangent, I was thinking about mathematical proofs and time. Is a mathematical idea eternal or does it exist in time? Can it be erased? Consider problems that are undecidable: they cannot be solved by shortcuts, but must be decided by actual computation that may or may not ever complete. If an undecidable algorithm completes to a decision, was the truth of that operation 'true but just not known before the computation completed' or does that truth spring forth at a particular time? Mathemtatics is a formal system which is written down symbolically in a physical medium. If all information of a mathematical theory were to be erased, is the theory still true or can it 'come out different' next time?

By: Nquire

Nquire — Tue, 25 Apr 2006 17:48:19 -0800

For anyone tired of trying to wrap their minds around the different interpretations of quantum mechanics, try John G. Cramer's Transactional Interpretation. Here's a powerpoint slideshow that explains how the transactional interpretation resolves Schrodinger's Cat and other classic paradoxes, and is simple enough that anyone playing with ripples in water can understand it - so long as one thinks of the time dimension as the surface of the water.

By: loquacious

loquacious — Tue, 25 Apr 2006 18:13:43 -0800

Scott Arronson is a total dick, and much less intelegent then he thinks he is. Please don't make me hurt you. Lie to me. Tell daddy that the typo in question was intentional.

By: Parannoyed

Parannoyed — Tue, 25 Apr 2006 18:15:34 -0800

ow! I think my pre-frontal cortex just cramped.

By: stavrosthewonderchicken

stavrosthewonderchicken — Tue, 25 Apr 2006 18:22:14 -0800

Great post. I love this stuff, and have been listening to some lectures on it recently. The puppy thing left me a bit cold, though. It seems clumsy to me to use macro-level metaphors like these (salad? steak?) to talk about probabilistic quantum states. much less intelegent then he thinks he is This is funny. [/spelling nazi]

By: stavrosthewonderchicken

stavrosthewonderchicken — Tue, 25 Apr 2006 18:22:41 -0800

Whoops. loquacious beat me to the snark.

By: Loto

Loto — Tue, 25 Apr 2006 19:55:13 -0800

This makes me love being a physics major. Thanks!

By: delmoi

delmoi — Tue, 25 Apr 2006 20:02:43 -0800

Please don't make me hurt you. Lie to me. Tell daddy that the typo in question was intentional. Lol, of course it was, of course it was.

By: ozomatli

ozomatli — Tue, 25 Apr 2006 21:32:06 -0800

Nope, didn't blow my mind.... I am a theoretical physicist though. Nice post though, the condescension in the fpp irked me a bit.

By: jmhodges

jmhodges — Tue, 25 Apr 2006 21:55:58 -0800

I'm not sure what you thought was condescending in the post. I posted the difficult links first because I wanted people to get a glimpse of what the field "really" looks like (esp. those with an interest) only to follow these links with "reach out" pages to keep the interest of those who aren't going to sit around for the derivation of IP=PSPACE. Most people only get a chance to see the latter and giving them the opportunity to poke at the hard stuff is pretty novel. This post wasn't made "for" theoretical physicists and the last two lines should have made that clear. Plus, the "blow your mind" bit was me being sarcastic. Specifically, I was thinking about a joke in the Daily Show's America textbook ("If pro is the opposite of con, what's the opposite of progress? Congress. Or did I just blow your mind?"). Everybody does a Keanu Reeves "Whoa" when they learn this stuff and physicists keep doing it or their research and teaching becomes lame. To paraphrase someone smarter than I: if quantum mechanics doesn't blow your mind, you don't understand quantum mechanics.

By: ozomatli

ozomatli — Tue, 25 Apr 2006 22:04:09 -0800

Don't worry about it. I am in a cranky mood because my apartment has been invaded by bees. I encourage everyone to be informed about modern physics, but my experience (and email inbox full) with crackpots who just read some pop-sci book on quantum mechanics tends to make me a bit more cynical than I should be. I really don't think it is possible to have a deep understanding of QM without doing the math. I recommend Griffith's Intro to Quantum book to anyone who wants to learn about QM. All of the flash demos and pop-sci books can never replace actually getting into and playing with Schrodinger's EQ. Again, sorry about the negative tone of my first post.

By: jmhodges

jmhodges — Tue, 25 Apr 2006 22:35:00 -0800

Not a problem, didn't mean to come off as snippy but I did. Also, I second your recommendation of Griffiths'. That thing will be on the shelf of Easy Reaching for years to come, if only to lend it out.

By: VirtualWolf

VirtualWolf — Tue, 25 Apr 2006 22:44:18 -0800

I read the puppy article. I still don't get it. :P

By: flabdablet

flabdablet — Wed, 26 Apr 2006 06:17:55 -0800

I don't get it either. Sleeping puppies are piss-poor salad-detection devices. ISTM that unless either (a) you wake a puppy (b) no puppy-waking occurs despite strong provocation, you can't reliably say whether there's a puppy in there. I can't see how waving very-probably-salad under the nose of a sleeping puppy actually constitutes a measurement of steakhood, even from the assumed puppy's point of view, unless the puppy happens to wake up. It further STM that there's a necessary tradeoff between the reliability of any such puppy-detection procedure and the total amount of provocation offered to the possible puppy. Didn't Heisenberg once work out something along those lines? IANATP, obviously.

By: 6am

6am — Wed, 26 Apr 2006 06:17:58 -0800

yeah but despite it's crackpottery, what the bleep do we know does try to remind people that how you think determines how you act - and that you can change the way you think. which is a good message.

By: flabdablet

flabdablet — Wed, 26 Apr 2006 06:18:30 -0800

Oh, and thanks for the t'Hooft link. That's gonna keep me busy for a while :^)

By: Farengast

Farengast — Wed, 26 Apr 2006 13:36:53 -0800

I must second Ozomatli's recommendation. Griffith's QM is a really excellent text.

By: Smedleyman

Smedleyman — Thu, 27 Apr 2006 10:41:32 -0800

Doesn't blow my mind, (gut maybe), I love this stuff. As a Taoist, non-destructive quantum measurement makes total sense to me. I get it. ....crap, I just blew it. "I can't see how waving very-probably-salad under the nose of a sleeping puppy actually constitutes a measurement of steakhood, even from the assumed puppy's point of view, unless the puppy happens to wake up." flabdablet, I suspect they're measuring functions of bits which describe the superpositions of the puppy, steak, salad, etc, not the bits themselves. Ergo, no full puppy waking required. You're sliding calculations under the curve of possibility, we and the puppy leave the salad/steak in it's superpositional state. Kinda reminds me of the Monty Hall three door thing in terms of counter-intuitiveness.

By: Smedleyman

Smedleyman — Thu, 27 Apr 2006 10:42:37 -0800

Way cool post btw jmhodges

By: sonofsamiam

sonofsamiam — Thu, 27 Apr 2006 10:50:58 -0800

Kinda reminds me of the Monty Hall three door thing in terms of counter-intuitiveness. Very astute. The solution to both problems depends on recognizing the partial information available to the observer, which is inextricable from the process that led to the observation. Consider this variant of the Monty Hall problem: Right after you picka door, but before Monty opens a door, there is an earthquake, and one of the other doors flies open, revealing no prize inside. "Oh well" says Monty. "Just pick from the remaining two doors." Should you switch doors? At first blush, this is the exact same problem, but the process which led to the state of knowledge is different and it does affect the answer.

By: sonofsamiam

sonofsamiam — Thu, 27 Apr 2006 10:55:28 -0800

Bell's Inequalities --what does it mean that there are no "hidden variables"? Quantum Mysteries Disentangled --what is the connection between "entanglement" and "observation"?