irrelevance (requires at least a hobbyistic interest in quantum physics

[willieray]

Just thinking late when i should be sleeping (whatever should be sleeping means) about some profound but rudimentary quantum physics. If you are (and you should be) aware of the simplest proof of quantum existence, that photons behave as waves unless measured as particles and then behave as such, REGARDLESS of when observation takes place (which more than suggests that information can travel backwards through time.... really, no joke), then (and my million $$$ question): if you run a two slit quantum photon test (shine a light thru a filter with two slits cut into it onto a piece of film), and use a device to measure which slit the photon passed through, BUT you destroy the results of the said measurement before anyone can observe it, does the film reflect the photon retaining quantum status and behaving as a wave, or does it behave as a particle ? I guess my question is: does quantum state require a lack of conscious observation, or the potential for it?

sorry if its not incredibly clear. in its current elusive state, i'm lucky i nailed down my questions so articulately, which isn't saying much. :)

~willieray

[dezrock]

Whenever you perform this experiment, you'll just wind up with a dead cat in a box somewhere. The next question is, where?

[GreyGeek]

Your question is similar in nature to the old classic: "If a tree falls in a forest and no one is around to hear it, does it make any sound?" but considerably more intriguing. Unfortunately, there is no way to answer you question without doing what your experimental setup prevents: examing the results.

A similar question: What happens when the unstoppable force meets the unmovable object?

[Dog-One]

What happens when the unstoppable force meets the unmovable object?I'd have to say that the vector of the unstoppable force is changed or dissapated at a point of least resistance.

does quantum state require a lack of conscious observation, or the potential for it?Fundamentally, I've always thought that matter and energy obey physical laws. The observation of such may be why better formulations like String Theory now exist.

[willieray]

Some good insights and thoughts. GreyGeek, examining the results of the experiment would be to simply observe the film. We have a device that measures which slit the photon (in particle form) passed through, but we do not observe the measurement it made. No conscious mind will ever observe this measurement. Now will the film reflect a wave pattern or a particle pattern? This experiment is doable and the results can be verified via the film.

[CrystalCowboy]

Some good insights and thoughts. GreyGeek, examining the results of the experiment would be to simply observe the film. We have a device that measures which slit the photon (in particle form) passed through, but we do not observe the measurement it made. No conscious mind will ever observe this measurement. Now will the film reflect a wave pattern or a particle pattern? This experiment is doable and the results can be verified via the film.
There is nothing in quantum theory that says the "observation" must be done by a conscious entity. IMNSHO the photon is "observed", i.e. it's waveform is collapsed or whatever, when it strikes the film.

[inha]

There is nothing in quantum theory that says the "observation" must be done by a conscious entity. IMNSHO the photon is "observed", i.e. it's waveform is collapsed or whatever, when it strikes the film.

correct. that's when the measurement happens. not when you take a look at the film.

all these philosophical/paradoxal aspects are interesting and all but there's nothing quite like just solving them schrödingers.

addition: both unstoppable force and inmovable object require the existence of infinite energy. that's quite unphysical, don't you think?

[willieray]

not when it hits the film, when our detector takes the measurement as the photon passes through the filter with the slits:

In a slightly different guise, this notion has its roots in an old experiment performed by Thomas Young in 1801 to prove that light is a wave, not a particle. Young cut two parallel slits close together in an opaque screen, shone a light on them, and observed stripes of light and dark, an interference pattern, where the light struck a wall beyond the slits. He argued that if light consisted of particles travelling in straight lines, they would go through the slits and create two bright patches. But because light is a wave, the crests and troughs emerging from the slits can either reinforce each other or cancel each other out, creating brightness in some places and darkness in others.

Now switch to photons. They are particles, so they ought to create two bright spots. Except that unlike classical bullets, they interact like waves. They are particles with wavelike properties. Or if you like, they are waves that behave like a stream of particles. Just as the partially silvered mirror in an interferometer "splits" the photons, so Young's slits divide each photon into two pieces, which interfere with each other beyond the screen to create the striped pattern on the wall. These "pieces" of photons aren't detectable: if you place detectors right up against the slits, to see which way the photons are going, you'll destroy the interference pattern. If you demand to see the photons acting like particles, going through one slit or the other, you lose the wave behaviour that creates the bright and dark stripes. You can see photons acting like waves, or you can see them acting like particles, but not both at once.

from http://www.newscientist.com/hottopics/quantum/weirdatheart.jsp

[CrystalCowboy]

For anyone who wants to claim that a conscious observer is necessary, I would ask which of these qualify:
a human
a monkey
an insect
an amoeba
a bacterium
a virus
a rock

[willieray]

Upon closer review (and after getting some much needed sleep), i don't think this is much of a mystery wrapped in this riddle of photon behavior. I think (being that i don't have a lab to test and observe and therefore know) that it is in taking the measurement of the locality that photons lose their wave behavior. The uncertainty principle basically assures this. Oh well it was fun to think about.

[Shadow Skill]

You know there is another problem with the supposed need for a conscious observer..we have no real idea what it is to begin with. Our consciousness like mathematics is purely a construct, we have no way of proving it is there at all in a truly scientific sense. [For those of you ready to dispute the fact that math is a construct keep in mind that people invented various equations and theorems, and that zero for example is a relatively recent edition to mathematics, there is a specific ancient culture that didn't have zero at all (I can't remember if it was the Greeks or not.)] The brain does not qualify as the mind even though it can be physically affected in ways that affect the mind, just like our hdd's are not our OS's even when like the brain one may physically affect a hard drive to change OS behavior.

[Jman]

The way the question was posed seemed to point to an impossible experiment: to not observe something because doing so would ruin the experiment, then make a conclusion. I like the uncertainty principle solution better.

Quantum principles bring up all kinds of crazy situations and paradoxes. Who would have thought that a quantum discussion of light would lead to speculation of consciousness?

By the way, the Greeks did not need a well defined zero, they had geometry. And zero appeared for sure by 650 AD (http://www-gap.dcs.st-and.ac.uk/~history/HistTopics/Zero.html).

[Shadow Skill]

Thanks for the link I could never remember it's specifics.

[salaneking]

If the universe is finite, what is outside it? If it is infinite how can it be unlimited in size?

[inha]

It cannot be unlimited in size I think. Again that would require infinite energy or the energy density of the universe would be zero.

What's outside it? Nothing I guess. The universe is all there is.

[sailor]

If the universe is finite, what is outside it? If it is infinite how can it be unlimited in size?
This brings up another question:
How small can something be? electrons, protons, neutrinos...etc are there smaller particles?
Is our universe merely a particle in the atom of some other universe?

[willieray]

This brings up another question:
How small can something be? electrons, protons, neutrinos...etc are there smaller particles?
Is our universe merely a particle in the atom of some other universe?

Absolutely. But the real question: does that ubermacrouniverse actually exist? And does the universe of sub quark particles exist? A very intelligent friend of mine argued that if something is so small (or large for that matter) that it does not have observable effects on our reality, than it does not exist. i like to liken his argument to integration (or derivation). approach an infinite limit and his ideas take shape.

Now back to the absolutely part of my post ;-) . look at the advances just in observations in our lifetimes. When i was a kid there were 4 food groups (meat being most important) and only 3 states of matter. Now there are at least 6 (solid, liquid, gas, plasma, bose-einstein condensate, and another condensate who's name escapes me now) known states. the last 2 show that under cerain conditions (usually removing lots of energy via cooling) that atoms form lattices that behave as macro atoms, effectively creating larger versions of the atoms themselves. Very odd but somehow intuitive.

more coming as my head dispenses it :D

~willieray

[willieray]

And in the words of that braintrust amongst men Ogre: "What if c-a-t really spelled dog?"

[inha]

well the electron is already basically a point object with mass. it's usually represented by the dirac delta function.

there's some speculation on wether quarks have internal structure or not. so far no experimental results confirm that there is but I really don't know what happens once we manage to build bigger and better particle accelerators. the smaller the scale is the more it's all about the energy baby.

which brings me to the one thing that really interests me, the exsistence of the higgs particle. if my memory serves me correct we should know if it exists or not by 2007. it'll answer a lot of questions about the nature matter and mass if it's detected.

or maybe it was 2005. the new accelerator is ready next year. possibly. I've got to go google this and check my facts.

edit: 2007 it is. I never should doubt myself.

[Jman]

It cannot be unlimited in size I think. Again that would require infinite energy or the energy density of the universe would be zero.
If the universe was infinite and had a finite amount of energy, the energy density would be close to zero, but not quite. Think effectively zero but a tiny bit more. If it was zero there would be no energy.

But why can't there be an infinite amount of energy in an infinite universe? My infinite math is not very well developed, so I'm not sure what that average it.

Somewhat back to the origional topic, if there is a Higgs particle which generates a Higgs field which is somehow related to matter, does more quantum weirdness occur? Does matter exist whether it is observed or not?

[sailor]

The universe is more likely to be infinite, but I don't see why it would mean zero or almost zero energy density.
There has got to be plenty of matter floating around just waiting to be converted ...in the next "big bang".

[inha]

If the universe was infinite and had a finite amount of energy, the energy density would be close to zero, but not quite. Think effectively zero but a tiny bit more. If it was zero there would be no energy.

But why can't there be an infinite amount of energy in an infinite universe? My infinite math is not very well developed, so I'm not sure what that average it.

Somewhat back to the origional topic, if there is a Higgs particle which generates a Higgs field which is somehow related to matter, does more quantum weirdness occur? Does matter exist whether it is observed or not?

I suppose it would be effectively zero. The thing with infinities is that.. well, they're infinite. Divide something finite into infinite fractions and what you get is zero.

There has to be finite dimensions and finite energy for the universe to "work right". If you want a more through explanation I'm going to have to through my textbooks a bit.

The Higgs field will not create more paradoxes or anything. It'll just tell us something more about the properities of matter. It's observation matters to me for sure. Things work just fine now but it'll answer one of those great why-questions in modern physics.

[sailor]

There has to be finite dimensions and finite energy for the universe to "work right".

Don't you mean "work right" given our limited knowledge of how the universe works. Isn't matter really a storage medium for energy? Energy may be finite only because it has not been released from the matter that contains it? I think we make incorrect assumption as to the "emptiness" of space.

[inha]

finite amount of matter means finite amount of energy. the space is not empty indeed. we're still missing some energy that accounts for the expansion speed of the universe. dark matter and dark energy are things we're constantly learning more about.

but this is getting seriously off my scope since cosmology isn't exactly a strong point in my knowledge in physics.

[sailor]

I am just curious about this...and I certainly lack the education on such things, but I do find it very interesting...sorry about getting off of the topic.

[willieray]

Look at all the discussion and interaction i've induced, and NO reputation points for this thread!?!? ;)