A boost for quantum reality: the wave function is real!

[Jarvitä]

Long suspected and hotly debated, the wave function, treated as "merely" a useful mathematical tool since its discovery, has now been conclusively proven to be "real", ie, to accurately reflect the actual reality of how the universe works.

Quantum states are the key mathematical objects in quantum theory. It is therefore surprisingthat physicists have been unable to agree on what a quantum state represents. One possibility is that a pure quantum state corresponds directly to reality. But there is a long history of suggestions that a quantum state (even a pure state) represents only knowledge or information of some kind. Here we show that any model in which a quantum state represents mere information about an underlying physical state of the system must make predictions which contradict those of quantum theory.

http://arxiv.org/pdf/1111.3328.pdf

 

[Ghostrider]

So, the quantum of solace is not lost?

 

[Donamy]

Anyone ever tried this ? While driving on the highway, look at the spinning hubcap of the car on your left, you see it as a blur, because it's spinning to fast to see it. Now look away very quickly, the hubcap freezes and you see it for a fraction of a second, not spinning. Weird :shrug:

 

[Keatah]

blink fast and stroboscopically freeze it. same thing and cameras usually work the same way.

 

[Tommy]

Anyone ever tried this ? While driving on the highway, look at the spinning hubcap of the car on your left, you see it as a blur, because it's spinning to fast to see it. Now look away very quickly, the hubcap freezes and you see it for a fraction of a second, not spinning. Weird :shrug:

This has to do with "persistence of vision". For instance, a fluorescent light "blinks" on and off 60 times per second (in the US, I think 50 times in Europe). Yet we see it as a steady light.

It's the same for movies - the screen is actually dark more than it is lit, but our vision "retains" the image through the darkness. The vision center of our brains "remembers" the last image it received until a new image is presented, or about 1/25 of a second if no new image is processed. That's why movies are filmed at ~29 fps - any slower and the "flicker" becomes apparent and distracting.

 

[Cras]

Movies are filmed at 24 frames a second. Television is shot at almost 60 fields a second, which translates down to near 30 frames per second.

 

[Black Phoenix]

Anyone ever tried this ? While driving on the highway, look at the spinning hubcap of the car on your left, you see it as a blur, because it's spinning to fast to see it. Now look away very quickly, the hubcap freezes and you see it for a fraction of a second, not spinning. Weird :shrug:

The perception in middle of your vision (+- 10 degrees) and to the sides is different. Details are perceived mostly in the middle, while motion and sudden changes in brightness are perceived mostly in edges of your vision (it's a good thing to know when avoiding obstacles). Sudden eye motions can cause erratic feeling about picture you're seeing (not only your head/eye rotate so you don't see blur as described in the post above, but you also perceive erroneous motion or no motion of the object - which is probably what made you notice this in the first place).

I prefer interpretation of QM as a good way to describe reality, just as the common newtons equations of motion. Just like the material point describes lots of things, but is not a real object, the wavefunction is also a convenient function which can be both exponent and linear (nearly linear).

"System has a real physical state not necessarily completely described by quantum theory, but objective and independent of the observer" - one of things to say is that the way you measure heavily affects what you're seeing (more commonly known as "looking at something changes its state").

The article seems to talk on whether wavefunction describes all of the system, rather than whether it's something entirely real. The less interesting answer is that for any complex systems building and solving all the equations is not possible, so it's hard to check it precisely.

 

[Tommy]

Movies are filmed at 24 frames a second. Television is shot at almost 60 fields a second, which translates down to near 30 frames per second.

My bad, yes, film is shot at 24 fps - and displayed at 72 fps (each image flashed three times) in modern projectors. TV is displayed at 29.something fps. Also, memory failed about the "interval" the visual cortex holds an image - it's about 1/15 seconds, not 1/25 as I mis-remembered earlier.

For accuracy's sake, NTSC TV (ie, US TV) is shot at 59.94 interlaced fields per second, giving an effective frame rate of 29.97 FPS.

It's interesting to note that modern video formats (including digital) are artificially limited to about 30 fps - because it looks "filmed" and people seem to prefer it. Go figure!

 

[jedidia]

From quantum mechanics to optics in 2 posts. Impressive! :tiphat:

 

[Ghostrider]

It's interesting to note that modern video formats (including digital) are artificially limited to about 30 fps - because it looks "filmed" and people seem to prefer it. Go figure!

60 fps has been commercially available since a while and it's an option on most camcorders even in the medium-low level (mine has a 720p at 60 fps setting for instance and it's hardly hardcore pro material). The problem with it is that it's so similar to real-life visual fluidity that it causes some "uncanny valley"-like effect because you know you're seeing a recorded or manufactured imagery, but your brain perceives it as real. Oddly enough, it causes less issues with videogames (which yield 60 fps) because the graphics aren't enough life-like (yet) to make our brain go all Hulk Smash inside our skulls.

That and the fact that jerky motion at 60 fps can cause some major motion sickness to people who already have it at lower frame rates, in my experience. The POV moves, you don't, your brain knows it but gets contradictory signals and sends its own brand of error message in the form of nausea waves.

From quantum mechanics to optics in 2 posts. Impressive!

Yes. We've gone offtopic. Yo, Asgardians! Moderators! Isn't there a "cool video" thread we can shift those posts to?

 

[RisingFury]

- "Quantum wave function is real!!!"
- "Oh, that's why my eyes have blurred vision!!!"

 

[SiberianTiger]

So, if that thing is real, is there any physically meaningful explanation, how can it be "destroyed" by a fact of observation?

 

[PhantomCruiser]

...We've gone offtopic. Yo, Asgardians! Moderators! Isn't there a "cool video" thread we can shift those posts to?

Well, there is the internet video thread (in which cool is in the eye of the beholder), there's the Orbiter video thread (which is often cool). But I don't know of a just plain cool video thread.

I was too wrapped up in some of the observations (the hubcap/wheel one is cool, as are ceiling fans) to even notice the off-topicness, but I can mention a generic note in to stay on topic if you want...

Note begins
Hey folks, stay on topic please.
Note ends

And now back to things quantum.
Didn't I read somewhere that observation of an experiment in and of itself alter the results of said experiment at the quantum level?

It was quantum theory course that led me to believe that (after 25 years as electronics technician), that I didn't know diddly about electronics. There are some PN junctions that cause electrons act in a very strange manner.

I'm still muddling my way through the article, pretty cool...

 

[Jarvitä]

So, if that thing is real, is there any physically meaningful explanation, how can it be "destroyed" by a fact of observation?

It isn't destroyed, a wave function collapse is triggered (ie, the predicted superposition of state vectors is reduced to a single amplitude configuration). And the term "observation" is in my opinion too anthropomorphic, seeing as how the overwhelming majority of state vector collapses are triggered by events other than human observation. This is easily evident by just how difficult it is for scientists to cause any macroscopic amount of matter to not collapse, even for trivial lengths of time.

---------- Post added at 13:45 ---------- Previous post was at 13:41 ----------

- "Quantum wave function is real!!!"
- "Oh, that's why my eyes have blurred vision!!!"

Everett mode:

- "Quantum wave function is real!" (ok, he got this one right a few decades before anyone got around to proving it, credit where it's due)
- "Therefore, there are an infinite number of universes, each collapse branching along its Bayes network!"
- "Modus ponens, it's OK to kill yourself since you'll always stay alive in n of them. Quantum immortality!"

 

[Cras]

So is the concept that information cannot be passed along a collapsing wavefunction still the method to claim it does not violate special relativity?

 

[Jarvitä]

So is the concept that information cannot be passed along a collapsing wavefunction still the method to claim it does not violate special relativity?

What?

Parsing...syntax error, does not compute.

 

[Linguofreak]

(ie, the predicted superposition of state vectors is reduced to a single amplitude configuration).

I've got a question here that I'm not sure if I know enough about the vocabulary and math of quantum physics to ask coherently:

Does wavefunction collapse actually result in a single amplitude configuration / pure state in practice, or is that just an on-paper thing assuming ideal conditions (akin to the assumption of spherical blackbodies in a vacuum in thermodynamics)?

 

[Jarvitä]

I've got a question here that I'm not sure if I know enough about the vocabulary and math of quantum physics to ask coherently:

Does wavefunction collapse actually result in a single amplitude configuration / pure state in practice, or is that just an on-paper thing assuming ideal conditions (akin to the assumption of spherical blackbodies in a vacuum in thermodynamics)?

Think of it as a "normal" observation. You want to observe an event, and have a probability distribution of outcomes. Once you observe it, the posterior probability distribution is revised by the observed outcome multiplied by the "strength" of the observation, ie, the probability of the observation itself being correct.

The observer effect isn't limited to quantum physics and it has nothing to do with human observers. You can notice it in the macroscopic world when trying to measure electric current or potential difference - as either zero or infinite resistance in the instrument is impossible to achieve, it will always effect the measurement itself. When you get to the level of sub-atomic particles, even individual photons have profound effects on the observed system.

Myself, I'm not at all convinced that there ever is a "single" self-state vector. Research, this article included, seems to point in the direction of the universe being inherently probabilistic.

 

[jimblah]

Search threads by "Latex count"?...

In a lecture from Caltech entitled 'A Universe from Nothing', Lawrence Krauss http://www.youtube.com/watch?v=7ImvlS8PLIo makes the comment 'If I'm not using mathematics to describe something, I'm lying to you.' English is the only language I speak fluently, and I'm appalled at the many contextual disparities it possesses. We should be able to devise a way that lists the number of Latex entries in a thread, especially in 'Math & Physics' and especially when mentioning quantum/wave anything.

P.S. I like to leave something in Latex that's cute, funny, and applicable... but this isn't my computer and Latex isn't installed.

 

[Jarvitä]

P.S. I like to leave something in Latex that's cute, funny, and applicable... but this isn't my computer and Latex isn't installed.

Use the [MATH] tags.[/MATH]