Macro Quantum Effect witnessed: Implies time travel? Multiple Universes?

Factual Questions
1

First the cool part. It seems some scientists have witnessed a macro object in a quantum (superimposed) state. The thing is still tiny but large enough to see with the eye unaided.

Here’s an article on it.

Now, turning to a much less reliable news source this article at FOX suggests this implies that time travel may be possible as well as many universes.

Many universes I get although I do not think this makes that theory any more likely than it was before. How does this imply time travel (even if a practical impossibility) could work? I read the article but it is not very good.

2

The Fox article seems to consist of “Quantum superposition is magic! Time travel is magic! We can work magic!”

As far as I know, there’s no way to interpret this finding as a step toward time travel.

3

I don’t know much physics. But I do know those articles are extremely poorly and even misleadingly written. I know it because, even after reading them, I don’t really have any idea what the experimenters set up, what observations they then made, and why that should be interpreted in all the various (often nonsensical) ways the articles say it should be.

4

The article said that the paddle was in it’s quantum-mechanical ground state. Uh… wouldn’t that be absolute zero, which nothing can reach?

5

It was very cold. They’re looking at the vibration of the paddle, which is macroscopic, so the next energy level of the paddle from its ground state could be very large relative to the energy it would take to make a single atom vibrate. The residual energy of heat in the paddle and any surrounding gas molecules could be small enough that it couldn’t excite the paddle out of its ground state, even though the temperature wasn’t all the way down to absolute zero.

6

After reading a few paragraphs of the object simultaneously moving and not moving, when I read this in the article “The work is simultaneously being published online today in Nature and …”

I thought they were going to finish it with " not being published today in Nature…".

7

“Best Joke In A Thread Actually Relevant To The Thread” Award :slight_smile:

8

Ok, I read both articles. IANA physicist of any kind but IMHO the Fox article is mash-up of a bona fide science experiment, a theory that is interesting but probably unfalsifiable (multiple universes), and another idea that IMHO is not quite even a theory (time travel), and draw wild conclusions about how these things are related.

The Fox reports understands just enough to be dangerous and has made some specious links from the experiment to these two theories.

9

Here is a pretty good critique of the Fox article by a physics grad student:

http://scienceblogs.com/builtonfacts/2010/04/the_worst_physics_article_ever.php

10

Thanks…kind of what I suspected. Witnessing this thing in a superimposed state is cool because of the scale but it is not something scientists were previously unaware of. Just no one thought it could be done on a macro scale (although the article suggests some other macro quantum effects we are familiar with but personally I didn’t think those were like this).

11

Missed the edit window and wanted to add:

I guess the most charitable thing we can say about these articles is that the scientists brought quantum weirdness into the macro world which, presumably, suggests we can harness that weirdness to do hitherto unthinkable things.

Of course this thing is still tiny so scaling it up to something we could use presents serious problems. Like one article noted this is why we do not see a bus moving and not moving at the same time. It is just suggestive that, theoretically if not practically, we could do that. The quantum weirdness is not restricted only to the super tiny world.

That blog article seems a little dismissive though of what was done. He seems to think it is cool but is a little blasé about it. Seems to me for the first time we are able to see the cat both dead and alive at the same time with our own eyes which is rather remarkable.

12

I read the article and found it something of a tease. It didn’t answer the most obvious question that just about every reader is immediately going to have: What did they SEE when it was in the superposition of states?

Did some of them see it vibrating, and some not… or what? Did they video it?

13

If you observe the superposition, it collapses. So it’s impossible to see it in both states simultaneously.

14

Well, what does “observing” entail? Photons are still hitting the thing and bouncing off. Why does it matter if there is an eye or camera to receive those photons? How does the quantum device “know” that a particular photon entered a camera and thus should collapse the superposition?

15

If I understand the article correctly, what they “saw” was that the current in the electric circuit the paddle was wired to was in a state of superposition between the mode it would be when the paddle was vibrating and when it was not.

16

What does it mean to see something in a state of superposition?

17

The critique was spot on. I was screaming at the monitor reading the FOX News article and I’m a freakin’ history major! The Nature article, OTOH, was a good piece.

I suggest reading the comments on the FOX article. Besides “Christian scientists have been hypothesizing for centuries that understanding quantum physics is a gateway to understanding,” there was also a few great ones to the effect of, “I don’t care what scientists say, something’s either moving or it isn’t.”

18

From the Nature article:

I read that as their instruments, however they where set up, recorded ‘movement’ and ‘not movement’ at the same time.

19

That’s not helpful to me. What kind of thing was set up to potentially record “movement”? What kind of thing was set up to potentially record “not movement”? That is, what do these labels correspond to, instrumentally?

20

I can’t extract a whole lot of details from either of those articles, so I don’t know exactly what they were measuring for. But if I had to guess, I would say that both articles are misrepresenting what was actually measured. The whole point of quantum mechanics is that measuring collapses a superimposed state, so you can’t measure both states at the same time: You get one or the other.

BUT if you repeat the experiment many many times, and nothing else changes, then sometimes you’ll get one state, and sometimes you’ll get the other. If you’ve successfully eliminated or accounted for all the variables, all that’s left is quantum probability, so you can show that the state you happen to find when you measure is random, but with predictable odds.

So in this particular case, you take the paddle and reduce it to its ground state (not moving). The first excited (moving) state has some associated energy. We’ll call that energy… 5. In classical physics, you could say that it takes 5 energy to bump the paddle from ground state to its excited state. Any less and it just won’t make it out of the hole.

In QM, though, if you add, say, 3 energy to the paddle, then the paddle isn’t exactly the ground state or the excited state. It’s in a superposition of states with a total energy of 3. But since you can only observe the paddle at one quanta or the other, once you measure it, it will either be in the ground state or the excited state. (Or a higher excited state, but probably with a very low probability)

So you take the paddle, pelt it with 3 energy, and see if it starts wiggling. Then you drop it back down to ground state, pelt it with 3 energy, and see if it starts wiggling. Do this a lot. See what percentage of the experiments lead to wiggling. Compare that to expected percentages. Get misquoted by FOX. The end.
I’d really like to see the actual experiment, though. Has anyone found, say, a paper written by the actual scientists involved?