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scott wrote:
>> What are your dubious assumptions?
>
> That all the energy from the star/light bulb comes out equally in all
> directions in the form of 550 nm photons, and your eye has an opening of
> 2mm x 2mm.
>
> Obviously all the energy doesn't come out as visible photons, and you
> could probably do something clever with the spectrum to get a more
> accurate figure.
To say nothing of the absorption and scattering of the Earth's atmosphere...
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Invisible <voi### [at] dev null> wrote:
> scott wrote:
> >> What are your dubious assumptions?
> >
> > That all the energy from the star/light bulb comes out equally in all
> > directions in the form of 550 nm photons, and your eye has an opening of
> > 2mm x 2mm.
> >
> > Obviously all the energy doesn't come out as visible photons, and you
> > could probably do something clever with the spectrum to get a more
> > accurate figure.
>
> To say nothing of the absorption and scattering of the Earth's atmosphere...
Probably not nearly as important as the error introduced by assuming both star
and bulb emit only in the visible.
Otherwise, not such dubious assumptions at all!
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>> To say nothing of the absorption and scattering of the Earth's atmosphere...
>
> Probably not nearly as important as the error introduced by assuming both star
> and bulb emit only in the visible.
>
> Otherwise, not such dubious assumptions at all!
Well, at least he didn't say an LED or a flourescent tube or something
with a complex emission system. A normal light bulb and a star are
(AFAIK) both simple black body radiators, so you just need to know their
colour temperature...
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Invisible <voi### [at] devnull> wrote:
> >> To say nothing of the absorption and scattering of the Earth's atmosphere...
> >
> > Probably not nearly as important as the error introduced by assuming both star
> > and bulb emit only in the visible.
> >
> > Otherwise, not such dubious assumptions at all!
>
> Well, at least he didn't say an LED or a flourescent tube or something
> with a complex emission system. A normal light bulb and a star are
> (AFAIK) both simple black body radiators, so you just need to know their
> colour temperature...
That just tells you the peak power output. The total power output might not be
as much as an order of magnitude different, but it will be different.
In any case, for a lightbulb, less than 10% of that 100W will be visible. An LED
or fluorescent tube will emit mostly in the visible, so the power will be much
more accurate for this comparison.
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>> Well, at least he didn't say an LED or a flourescent tube or something
>> with a complex emission system. A normal light bulb and a star are
>> (AFAIK) both simple black body radiators, so you just need to know their
>> colour temperature...
>
> That just tells you the peak power output. The total power output might not be
> as much as an order of magnitude different, but it will be different.
I was under the impression that the colour temperature tells you roughly
how the signal power is distributed over the whole spectrum. (Initially
just IR, then red as well, and gradually more high frequencies, while
the power at lower frequences decreases.)
> In any case, for a lightbulb, less than 10% of that 100W will be visible. An LED
> or fluorescent tube will emit mostly in the visible, so the power will be much
> more accurate for this comparison.
Yeah, both stars and lightbulbs presumably put out far more IR and radio
waves than visible light...
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Invisible <voi### [at] devnull> wrote:
> I was under the impression that the colour temperature tells you roughly
> how the signal power is distributed over the whole spectrum.
Roughly, in that it tells you where the peak is and the general shape of the
rest of the spectrum.
> Yeah, both stars and lightbulbs presumably put out far more IR and radio
> waves than visible light...
Actually, many stars peak in the visible - Betelgeuse is red. Ours is yellow. I
think maybe lightbulbs peak in the IR (lower temperature), so all we see is a
section of the tail of the spectrum.
http://en.wikipedia.org/wiki/Black_body
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> Invisible <voi### [at] devnull> wrote:
>> I was under the impression that the colour temperature tells you roughly
>> how the signal power is distributed over the whole spectrum.
>
> Roughly, in that it tells you where the peak is and the general shape of the
> rest of the spectrum.
Sure. So if you know how hot the star is, you know roughly the shape of
the entire emission spectrum. :-)
>> Yeah, both stars and lightbulbs presumably put out far more IR and radio
>> waves than visible light...
>
> Actually, many stars peak in the visible - Betelgeuse is red. Ours is yellow. I
> think maybe lightbulbs peak in the IR (lower temperature), so all we see is a
> section of the tail of the spectrum.
The peak is just the single wavelength at which there is the most
energy. I think if you look at *bands* of the spectrum, it's possible
for a wide band with low energy at any specific single wavelength to
have a greater total power and a band containing only a single
high-power (but narrow) peak.
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> for a wide band with low energy at any specific single wavelength to
How can you have a "wide band" at a specific single wavelength? Surely the
definition of a "band" is a range of wavelengths?
Sure, if the peak is at 600 nm, then the energy in the band from 599.99 to
600.01 will most likely be less than the band from 100 to 599.
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scott wrote:
>> for a wide band with low energy at any specific single wavelength to
>
> How can you have a "wide band" at a specific single wavelength? Surely
> the definition of a "band" is a range of wavelengths?
>
> Sure, if the peak is at 600 nm, then the energy in the band from 599.99
> to 600.01 will most likely be less than the band from 100 to 599.
What I actually meant was that a "peak" is just one wavelength with a
lot of energy. The band containing the peak isn't necessarily the band
with the highest total energy.
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Invisible <voi### [at] devnull> wrote:
> Sure. So if you know how hot the star is, you know roughly the shape of
> the entire emission spectrum. :-)
Yes. Except of course it works the other way around in practice.
> > think maybe lightbulbs peak in the IR (lower temperature), so all we see is a
> > section of the tail of the spectrum.
>
> The peak is just the single wavelength at which there is the most
> energy. I think if you look at *bands* of the spectrum, it's possible
> for a wide band with low energy at any specific single wavelength to
> have a greater total power and a band containing only a single
> high-power (but narrow) peak.
What Scott said. But I know what you mean - and yes, of course. I was just
explaining why most of an incandescent bulb's energy output is not in the
visible. Look at the shape of a blackbody spectrum for 3000K. Clearly, most of
the power output is IR and beyond.
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> Probably not nearly as important as the error introduced by assuming both
> star
> and bulb emit only in the visible.
Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
bulb (2%) and LEDs (1.5-22%):
http://en.wikipedia.org/wiki/Luminous_efficacy
Whilst the % values are not exactly the amount of radiation that is visible
(it's weighted more towards green), it's a better approximation than 100%
:-)
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> Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
> bulb (2%) and LEDs (1.5-22%):
Anybody happen to know the luminous efficacy of a glow worm?
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>> Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
>> bulb (2%) and LEDs (1.5-22%):
>
> Anybody happen to know the luminous efficacy of a glow worm?
Man Wikipedia knows everything! We should power our lights with glow worms!
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"scott" <sco### [at] scottcom> wrote:
> >> Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
> >> bulb (2%) and LEDs (1.5-22%):
> >
> > Anybody happen to know the luminous efficacy of a glow worm?
>
> Man Wikipedia knows everything! We should power our lights with glow worms!
All they need is a reflective cavity and a biochemical population inversion, and
we could have them in CD players too!
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>>> Anybody happen to know the luminous efficacy of a glow worm?
>> Man Wikipedia knows everything! We should power our lights with glow worms!
>
> All they need is a reflective cavity and a biochemical population inversion, and
> we could have them in CD players too!
...so I'm guessing it's quiet efficient then? (Mother Nature has an
uncanny way of doing this, it seems.)
Given the number of genetically engineered organisms which glow, I'm
guessing scientists have a good idea of how this works. Maybe
electronically-controlled glowing algae or something isn't so
far-fetched. (I hate to think what the component lifetime would be though!)
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Darren New <dne### [at] sanrrcom> wrote:
> No. The "interference" is caused not by the particle, but by the slits.
How does the photon know there was another slit nearby, and behave
differently if that was so?
--
- Warp
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Patrick Elliott <sel### [at] npgcablecom> wrote:
> Warp wrote:
> > when the state of the particle is "observed" (whatever that might mean)
> Merely that you have done something to it which changes its unknown
> state, usually causing it to make contact with another particle(s), such
> as a detector.
I think the Copenhagen interpretation goes beyond that. If the decay of
the radioactive substance causes the flask to be broken, killing the cat,
it has already been "observed" (by whatever detector caused the flask to
be broken) and thus there are no superimposed states, but according to
the Copenhagen interpretation there are, until some external observer opens
the box.
That's the kind of "observation" I don't understand.
--
- Warp
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > It looks like a wave, it behaves like a wave, it produces all the effects
> > that a wave would produce, but it's not a wave.
> By the way, just so you know, this sort of statement comes across to me as
> sarcastic, as if you're ridiculing my statements. I don't know if that's
> your intention here, but that's why after a number of exchanges I sometimes
> get ruder than I need to be. I don't know if it's a communication issue or
> you getting frustrated at my inability to explain quantum mechanics in a
> 2-paragraph post ;-) but sometimes when you don't agree, your expressions of
> that lack of agreement (not necessarily disagreement, mind) sound sarcastic.
It was not sarcasm, it was puzzlement.
--
- Warp
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>> No. The "interference" is caused not by the particle, but by the slits.
>
> How does the photon know there was another slit nearby, and behave
> differently if that was so?
If you could answer exactly how a photon "knows" where it can and can't go
then you'd probably become quite famous.
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> No. The "interference" is caused not by the particle, but by the slits.
>
> How does the photon know there was another slit nearby, and behave
> differently if that was so?
Nobody knows.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Warp wrote:
> That's the kind of "observation" I don't understand.
They're still working on that one. Someone recently proposed it's actually
gravity waves causing the "collapse", which is why it doesn't happen until
you get enough particles that gravity becomes significant. Or some such.
That's another one of those "nobody is sure why yet" kind of things.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Warp wrote:
> It was not sarcasm, it was puzzlement.
I will keep that in mind, then. :-)
Generally speaking, as a native speaker of English, when you express
something like that as a statement rather than a question, it comes across
with an invisible "Yeah, right, pull the other one" kind of statement. At
least to me. Just so ya know.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > Darren New <dne### [at] sanrrcom> wrote:
> >> No. The "interference" is caused not by the particle, but by the slits.
> >
> > How does the photon know there was another slit nearby, and behave
> > differently if that was so?
> Nobody knows.
But it seems that everybody knows that it does not happen by the photon
going through both slits?
(After all, it would make sense: If there's no other slit to go through,
then it can't go through two slits, and thus its behavior is different than
if there was another slit and it went through both.)
Or is this again that kind of almost-supernatural phenomena like the
photon somehow knowing that one year from now it will be measured which
slit it went through and thus it will already know to not to produce the
interference pattern?
--
- Warp
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>> Darren New <dne### [at] sanrrcom> wrote:
>>>> No. The "interference" is caused not by the particle, but by the slits.
>>> How does the photon know there was another slit nearby, and behave
>>> differently if that was so?
>
>> Nobody knows.
>
> But it seems that everybody knows that it does not happen by the photon
> going through both slits?
Correct. Or, rather, nobody has ever measured anything that would imply the
photon goes through both slits as a wave. Nobody has ever measured the
actual wave-like nature of photons, other than that the probability you
measure one of those particles at a particular place shares much of the same
math as waves. (The probability that *two* photons do something does *not*
share the same math as waves.)
The photon, in some very rare cases, might go through both slits, but not at
the same time as a wave. Instead, it might actually go in a circle and go
through both. But it's vanishingly improbable, and maybe even impossible if
the probabilities actually add up to zero.
Essentially, every single time you find a photon, you find an entire photon.
There's never a case where you get a half a photon. Hence the "quantum"
nature of it all. You don't get half a photon just like you never ever find
an electron with half a charge, and just like you don't find a coin that
comes up half heads half tails. The only "interference" you get is patterns
when you measure where lots of photons go.
> (After all, it would make sense: If there's no other slit to go through,
> then it can't go through two slits, and thus its behavior is different than
> if there was another slit and it went through both.)
But it only goes through one slit if you measure which slit it went thru.
This is true even *if* you make the measurement *after* the slits. You never
see the photon going through both slits, like you would if it were actually
a wave.
> Or is this again that kind of almost-supernatural phenomena like the
> photon somehow knowing that one year from now it will be measured which
> slit it went through and thus it will already know to not to produce the
> interference pattern?
Again, it's not a question of one photon making an interference pattern.
It's a bunch of photons making an interference pattern. Any one photon shows
up all at once and makes a single discrete mark wherever it hits. It's just
more likely to hit in one area than another.
It's sort of like saying that at a sufficiently small scale, there aren't
waves in water either. If there's a "high" wave, you're more likely to see a
molecule of H2O high above the average surface level than if there's a
trough. You can calculate the probability of H2O molecules being in a
particular place, but you're never going to see an H2O molecule interfering
with itself. (At least, not in the "classic" size of water waves.) You can
ask "how does the beach get more wet near the waterline than higher up if
water isn't waves?" It's because you're more likely to find an H2O molecule
close to the waterline than higher up the beach. But that doesn't mean H2O
is made out of waves.
But in short, yes, it's the same weirdness, which is how people know it's
not waves per se. Being a wave would imply it's actually the photon itself
that's controlling where it goes. But we already know you can control where
the photon goes retroactively, which would obviously make no sense if it was
deciding based on being a wave. If it's interfering *because* it is going
through both slits, you wouldn't be able to change whether it went thru both
slits or not after it already hit the detector. There's something deeply
unintuitive going on that nobody understands.
BTW, it's also pretty easy to prove it's not something in the photon that we
can't measure controlling how it works. That's what Bell's Inequality is about.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New <dne### [at] sanrrcom> wrote:
> > But it seems that everybody knows that it does not happen by the photon
> > going through both slits?
> Correct. Or, rather, nobody has ever measured anything that would imply the
> photon goes through both slits as a wave.
The interference pattern in the detector is not a measurement?
> Essentially, every single time you find a photon, you find an entire photon.
> There's never a case where you get a half a photon.
But I thought that's the whole idea in the Copenhagen interpretation:
Particles are in superpositions until they are measured, in which case
they collapse into a definite state. Thus when you measure a photon, you
will always find a collapsed photon.
> > (After all, it would make sense: If there's no other slit to go through,
> > then it can't go through two slits, and thus its behavior is different than
> > if there was another slit and it went through both.)
> But it only goes through one slit if you measure which slit it went thru.
> This is true even *if* you make the measurement *after* the slits. You never
> see the photon going through both slits, like you would if it were actually
> a wave.
You also never see the cat in both live and dead states at the same time.
> > Or is this again that kind of almost-supernatural phenomena like the
> > photon somehow knowing that one year from now it will be measured which
> > slit it went through and thus it will already know to not to produce the
> > interference pattern?
> Again, it's not a question of one photon making an interference pattern.
> It's a bunch of photons making an interference pattern. Any one photon shows
> up all at once and makes a single discrete mark wherever it hits. It's just
> more likely to hit in one area than another.
Of course I implied that you perform the test many times and see the overall
pattern that the photons create.
--
- Warp
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>>> But it seems that everybody knows that it does not happen by the photon
>>> going through both slits?
>
>> Correct. Or, rather, nobody has ever measured anything that would imply the
>> photon goes through both slits as a wave.
>
> The interference pattern in the detector is not a measurement?
No. It's a bunch of individual measurements of different photons. There's no
way to look at *one* photon and decide whether there was one slit or two.
Because it's not a wave, it's a particle, so it always makes the same sort
of single-spot quantum event in a single place.
> But I thought that's the whole idea in the Copenhagen interpretation:
> Particles are in superpositions until they are measured, in which case
> they collapse into a definite state. Thus when you measure a photon, you
> will always find a collapsed photon.
If every time one measures something, one gets "it isn't a wave", then why
would one think it's ever a wave?
Particle *probabilities* are in superpositions. That doesn't make them waves.
But again, this is a question of "why does it work that way", and not "how
does it work", and AFAIK nobody knows the underlying reason why the
probabilities work out the way they do.
>> But it only goes through one slit if you measure which slit it went thru.
>> This is true even *if* you make the measurement *after* the slits. You never
>> see the photon going through both slits, like you would if it were actually
>> a wave.
>
> You also never see the cat in both live and dead states at the same time.
That's actually evidence for it being particles and *not* waves. :-)
>> Again, it's not a question of one photon making an interference pattern.
>> It's a bunch of photons making an interference pattern. Any one photon shows
>> up all at once and makes a single discrete mark wherever it hits. It's just
>> more likely to hit in one area than another.
>
> Of course I implied that you perform the test many times and see the overall
> pattern that the photons create.
Yes. But if a photon was a wave, it could interfere with *itself*. It could
split up and go through two separate slits. One photon doesn't make an
interference pattern, and that's how you know the photon isn't a wave. You
don't see half the photon's energy hit here and half hit there with a blank
spot in the middle.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > Darren New <dne### [at] sanrrcom> wrote:
> >>> But it seems that everybody knows that it does not happen by the photon
> >>> going through both slits?
> >
> >> Correct. Or, rather, nobody has ever measured anything that would imply the
> >> photon goes through both slits as a wave.
> >
> > The interference pattern in the detector is not a measurement?
> No. It's a bunch of individual measurements of different photons. There's no
> way to look at *one* photon and decide whether there was one slit or two.
> Because it's not a wave, it's a particle, so it always makes the same sort
> of single-spot quantum event in a single place.
That's like saying that you can't measure the probability of a coin
giving heads because you can only toss one coin at a time.
I'd say tossing 100 coins one after another is exactly as valid as if you
had tossed one coin 100 times simultaneously (if that was physically possible).
> > But I thought that's the whole idea in the Copenhagen interpretation:
> > Particles are in superpositions until they are measured, in which case
> > they collapse into a definite state. Thus when you measure a photon, you
> > will always find a collapsed photon.
> If every time one measures something, one gets "it isn't a wave", then why
> would one think it's ever a wave?
Because of the interference pattern?
If it behaves like a wave, what can we deduce from that?
> >> But it only goes through one slit if you measure which slit it went thru.
> >> This is true even *if* you make the measurement *after* the slits. You never
> >> see the photon going through both slits, like you would if it were actually
> >> a wave.
> >
> > You also never see the cat in both live and dead states at the same time.
> That's actually evidence for it being particles and *not* waves. :-)
It's an argument that measurement doesn't necessarily tell what was the
state before the measurement was performed.
> Yes. But if a photon was a wave, it could interfere with *itself*. It could
> split up and go through two separate slits. One photon doesn't make an
> interference pattern, and that's how you know the photon isn't a wave.
That just doesn't convince me. Just because the photon collapses when it
hits the detector doesn't mean that on the way it didn't pass through both
slits at the same time and interfered with itself.
It sounds like you are arguing that particles cannot be in superimposed
states and that there's no collapse phenomenon when they are measured, but
instead they are always at single places at a time, in particle form. In
other words, that the Copenhagen interpretation is wrong. (Of course, if
I have understood correctly, nobody has proven that it's right, but you
are seemingly claiming it's wrong. Has that been proven?)
(Not that I have the slightest idea what I'm talking about. The problem
I'm having is that, seemingly, people have no idea why the interference
pattern appears yet are completely sure it's *not* because photons are
in wave state at any point.)
> You
> don't see half the photon's energy hit here and half hit there with a blank
> spot in the middle.
You don't see it because if you try to see it, the photon collapses and
the only thing you see is a particle.
--
- Warp
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Warp wrote:
> Patrick Elliott <sel### [at] npgcablecom> wrote:
>> Warp wrote:
>>> when the state of the particle is "observed" (whatever that might mean)
>
>> Merely that you have done something to it which changes its unknown
>> state, usually causing it to make contact with another particle(s), such
>> as a detector.
>
> I think the Copenhagen interpretation goes beyond that. If the decay of
> the radioactive substance causes the flask to be broken, killing the cat,
> it has already been "observed" (by whatever detector caused the flask to
> be broken) and thus there are no superimposed states, but according to
> the Copenhagen interpretation there are, until some external observer opens
> the box.
>
> That's the kind of "observation" I don't understand.
>
But, the Copenhagen interpretation is intended as an example, where by
the "mechanism" isn't part of the system that causes the observation.
The presumption being that what ever opens the box to look is what
*causes* the result. It was never intended to be used to imply that the
state in such a box could/does exist in the real world. In short, you
are exaggerating the meaning of the example. There may be others doing
so too, but most understand that the *entire box*, and the cat inside,
is the particle, and that the observer is basically what ever "looks"
into the box to see what happened, which could be an X-Ray machine, for
all that it matters, or a guy with a crowbar, or just some single
particle, shot at the box, which "quantum tunnels" through the inside,
and other the other, carrying some information on the state inside. The
*observer* is never a conscious observer, it is always, "What ever
happens to interact with the particle, causing it to change."
And, if you think about it, it can't be otherwise. If you observe a
particle with a detector, the detector "causes" the state change. Turn
on a flashlight, photons cause the state change. There is no way to
*observe* an object that doesn't involve us hitting the particle with
another particle, and measuring what the change in *that* particle is,
thereby deriving what happened to the other one. All Copenhagen really
says is, "If nothing is interacting with the particle, the particle's
state isn't known, but the moment something does (which they confusingly
termed "observer"), the state becomes fixed." Its sort of like the way
normal people use "theory" to mean guess, but scientists mean, "already
supported by evidence". "Observer" doesn't mean what the average person
would mean by it. Imho, it was a really poor choice, but we are, at this
point, stuck with it. lol
--
void main () {
If Schrödingers_cat is alive or version > 98 {
if version = "Vista" {
call slow_by_half();
call DRM_everything();
}
call functional_code();
}
else
call crash_windows();
}
<A HREF='http://www.daz3d.com/index.php?refid=16130551'>Get 3D Models,
3D Content, and 3D Software at DAZ3D!</A>
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Darren New wrote:
> Warp wrote:
>> That's the kind of "observation" I don't understand.
>
> They're still working on that one. Someone recently proposed it's
> actually gravity waves causing the "collapse", which is why it doesn't
> happen until you get enough particles that gravity becomes significant.
> Or some such.
>
> That's another one of those "nobody is sure why yet" kind of things.
>
Ok. Already gave and answer to why this is odd, but.. Just to let you
clarify - How do you "measure" or "observe" what a particle as even
done, without colliding it with something? What process do you use that
doesn't involve a "state change" resulting directly from a scientific
instrument *causing* the state to change? There isn't one, so the
Copenhagen interpretation can't be arguing that "looking at something",
without actually, you know... "looking at it", does anything. By
definition, anything you can/do do, which looks at a particle, involves
*other particles*, so I am unclear what the heck either one of you are
claiming is different here from any other sort of quantum physics.
Again, we can't measure/observe a particle, without interacting with it,
so claiming that "changing" it by observation differs from changing it
by hitting it with another particle is just... not making any sense at all.
--
void main () {
If Schrödingers_cat is alive or version > 98 {
if version = "Vista" {
call slow_by_half();
call DRM_everything();
}
call functional_code();
}
else
call crash_windows();
}
<A HREF='http://www.daz3d.com/index.php?refid=16130551'>Get 3D Models,
3D Content, and 3D Software at DAZ3D!</A>
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>> Darren New <dne### [at] sanrrcom> wrote:
>>>>> But it seems that everybody knows that it does not happen by the photon
>>>>> going through both slits?
>>>> Correct. Or, rather, nobody has ever measured anything that would imply the
>>>> photon goes through both slits as a wave.
>>> The interference pattern in the detector is not a measurement?
>
>> No. It's a bunch of individual measurements of different photons. There's no
>> way to look at *one* photon and decide whether there was one slit or two.
>> Because it's not a wave, it's a particle, so it always makes the same sort
>> of single-spot quantum event in a single place.
>
> That's like saying that you can't measure the probability of a coin
> giving heads because you can only toss one coin at a time.
No. It's like saying a coin doesn't land half-heads-half-tails. You can
certainly measure the *probability* of a photon hitting in a particular
place. That doesn't mean the photon is or ever was a wave.
> I'd say tossing 100 coins one after another is exactly as valid as if you
> had tossed one coin 100 times simultaneously (if that was physically possible).
Yes. And even tho you get about half heads and about half tails, not a
single one of those coins wound up with half the heads showing or half the
tails showing. They were all either 100% heads or 100% tails, when you look
at each one individually.
Similarly, each photon is a particle, and it never goes through both slits,
just like a coin never lands 50% heads and 50% tails.
>>> But I thought that's the whole idea in the Copenhagen interpretation:
>>> Particles are in superpositions until they are measured, in which case
>>> they collapse into a definite state. Thus when you measure a photon, you
>>> will always find a collapsed photon.
>
>> If every time one measures something, one gets "it isn't a wave", then why
>> would one think it's ever a wave?
>
> Because of the interference pattern?
There's one set of measurements that give the same probabilities as if the
photons were propagating as waves. But there's also other ways to explain
the interference pattern (mathematically speaking) that has the same
arithmetic but a different interpretation. This different interpretation is
consistent with *all* the measurements.
It's like looking up at the sky and saying "The sun goes around the earth,
obviously." But yes, maybe the earth goes around the sun, and you'd get the
same appearance as the sun, but if you look at other *planets* you can tell
they're all going around the sun.
> If it behaves like a wave, what can we deduce from that?
If you flip 1000 coins, and it comes up 500 heads and 500 tails, can we
deduce that each flip landed half heads half tails?
> It's an argument that measurement doesn't necessarily tell what was the
> state before the measurement was performed.
But *no* measurement *ever* detects waves. They only detect distributions of
particles that match the mathematics of complex numbers. Waves also match
the mathematics of complex numbers. But not everything that matches the
mathematics of complex numbers is a wave.
>> Yes. But if a photon was a wave, it could interfere with *itself*. It could
>> split up and go through two separate slits. One photon doesn't make an
>> interference pattern, and that's how you know the photon isn't a wave.
>
> That just doesn't convince me. Just because the photon collapses when it
> hits the detector doesn't mean that on the way it didn't pass through both
> slits at the same time and interfered with itself.
Well, you're arguing the question that has confused nobel-prize-winning
physicists. I can only try to explain what I understand them to say. I can't
really convince you per se.
Nobody can figure out what would cause a "collapse", nobody has math that
explains when the collapse happens, nobody has ever observed a particle in a
non-collapsed state.
> It sounds like you are arguing that particles cannot be in superimposed
> states
No, I'm saying they aren't waves. What's superimposed isn't a "wave", but
probabilities. Yes, particles are in superimposed states. That doesn't make
them waves. Since the states particles can be superimposed and tangled up
with the states of other particles, and that tangling does *not* act like a
wave, then it's experimentally determined that superimposed states aren't
waves either. It only looks like a wave if you look at one of them.
> and that there's no collapse phenomenon when they are measured, but
> instead they are always at single places at a time, in particle form.
That's not what I said. You only ever *measure* them in a single place at a
single time in particle form. How would you really know what it's doing if
you never observe it doing it?
There are theoretical reasons to believe it's impossible to observe them
being waves. (Otherwise, they wouldn't be quantum, for example.) Indeed, the
whole "black body radiation" question that started quantum physics falls
down if photons are waves in flight, which is why people stopped thinking
they were waves in the first place: it was impossible to understand
something glowing hot if light is waves.
> other words, that the Copenhagen interpretation is wrong. (Of course, if
> I have understood correctly, nobody has proven that it's right, but you
> are seemingly claiming it's wrong. Has that been proven?)
I think people are still debating, but as far as I know, all the really
smartest people think quantum theory comes in quantums. :-) The whole
problem with the Copenhagen interpretation is that nobody knows why it would
collapse, nobody has any math to explain the collapse, and it doesn't give
you any answer better than you get with "it's never a wave", especially
without being able to explain why it collapses.
Maybe if someone knew what caused the collapse, or under what circumstances
it happened, you could test if Copenhagen was valid or not. But it doesn't
make any predictions the always-a-particle theory makes.
> (Not that I have the slightest idea what I'm talking about. The problem
> I'm having is that, seemingly, people have no idea why the interference
> pattern appears yet are completely sure it's *not* because photons are
> in wave state at any point.)
They know because when you actually put *two* photons together, they *don't*
make an interference pattern. If photons were waves, you wouldn't get
lasers, for example. And they wouldn't interact with electrons in the way
they do, even when you're not "observing" them.
I may have no idea if you start out in your automobile in your driveway
where you got to, but I'm pretty sure you didn't drive to Hawai'i. :-)
>> You
>> don't see half the photon's energy hit here and half hit there with a blank
>> spot in the middle.
>
> You don't see it because if you try to see it, the photon collapses and
> the only thing you see is a particle.
I think it's Occam's Razor here. Why postulate a quantum being a wave if (1)
no observation is capable of ever seeing it as a wave, (2) it behaves in
ways contrary to it being a wave when in flight, and (3) everything you *do*
see can be explained without it ever being a wave?
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Patrick Elliott wrote:
> Ok. Already gave and answer to why this is odd, but.. Just to let you
> clarify - How do you "measure" or "observe" what a particle as even
> done, without colliding it with something?
You don't. But you can make a measurement after it has done something, and
change what it "has done" already.
> definition, anything you can/do do, which looks at a particle, involves
> *other particles*,
Right. But it might involve *other* particles *after* the measurement of
interest has been completed.
> Again, we can't measure/observe a particle, without interacting with it,
Sure you can. Look up Bell's Inequality, or Quantum Erasers.
http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser
> so claiming that "changing" it by observation differs from changing it
> by hitting it with another particle is just... not making any sense at all.
That's what makes the copenhagen interpretation problematic, yes.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New <dne### [at] sanrrcom> wrote:
> I think it's Occam's Razor here. Why postulate a quantum being a wave if (1)
> no observation is capable of ever seeing it as a wave
I suppose that means that all phenomena caused by electromagnetic waves
(which light is) has to be explained by non-wave means, such as for example
electromagnetic radiation having a frequency and amplitude, as well as
exhibiting wave-like behavior such as polarization (how can you polarize
a particle given that polarization is by definition a property of waves
that describes the orientation of their oscillations?) and the effect
electromagnetic waves have on electric conductors (which is what radio and
TV broadcasts, among many other things. are based on).
The effect on eletric conductors is interesting: Electromagnetic waves
cause electrons to move at the same frequency than the frequency of the
incoming radiation, which clearly demonstrates that it does have a
frequency. The amount of movement is proportional to the amplitude of
the incoming radiation, which demonstrates that it does have an amplitude.
The amount of movement is also proportional to the direction of oscillation
of the incoming radiation (something which is also demonstrated by
polarization).
The double-slit experiment also demonstrates wave-like quality.
If it looks like a wave, feels like a wave, smells like a wave, what is it?
Not a wave, it seems. It just fakes being one quite well.
--
- Warp
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Patrick Elliott <sel### [at] npgcablecom> wrote:
> It was never intended to be used to imply that the
> state in such a box could/does exist in the real world.
AFAIK there's a big difference between an analogy and a thought experiment.
An analogy is describing in layman terms something complicated. The analogy
is not to be taken literally, but just as a way to visualize the concept
being explained.
A thought experiment, however, is something which should happen (even if
it's physically unfeasible to put into practice). It's not an analogy, but
an actual phenomenon which should happen if the theory is true and the proper
conditions could be set up.
Schrodinger's cat is a thought experiment, not an analogy.
> And, if you think about it, it can't be otherwise. If you observe a
> particle with a detector, the detector "causes" the state change.
But in the thought experiment the detector already measured the radioactive
particle and caused (or not) the hammer to break the flask. The cat itself
also observes what happens (quite literally). Yet the thought experiment
still maintains that (given that the inside of the box is completely isolated
from the outside), the cat is in two superposed states. Not as an analogy or
figure of speech, but literally.
If the solution were that simple, it wouldn't be a thought experiment
(with multiple possible explanations) at all.
--
- Warp
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> I think it's Occam's Razor here. Why postulate a quantum being a wave if (1)
>> no observation is capable of ever seeing it as a wave
>
> I suppose that means that all phenomena caused by electromagnetic waves
> (which light is)
I think it's not considered to be an electromagnetic wave any more.
> has to be explained by non-wave means, such as for example
> electromagnetic radiation having a frequency and amplitude,
Yep. Explained.
> as well as
> exhibiting wave-like behavior such as polarization (how can you polarize
> a particle given that polarization is by definition a property of waves
> that describes the orientation of their oscillations?)
Not in QM. I don't know too much about polarization, but it's not purely
based on "wave" stuff.
> and the effect
> electromagnetic waves have on electric conductors (which is what radio and
> TV broadcasts, among many other things. are based on).
Sure. Particles of light hitting the metal of the antenna and knocking
electrons around causes radio reception, for example.
> The effect on eletric conductors is interesting: Electromagnetic waves
> cause electrons to move at the same frequency than the frequency of the
> incoming radiation, which clearly demonstrates that it does have a
> frequency.
The change in quantum-amplitude has a frequency, because you're changing it
in a regular pattern at the transmitter.
> The amount of movement is proportional to the amplitude of
> the incoming radiation,
It's proportional to the number of photons arriving. If by "amplitude" you
mean "strength", then yes. If by "amplitude" you mean what people who talk
about QED mean, then no.
> which demonstrates that it does have an amplitude.
> The amount of movement is also proportional to the direction of oscillation
> of the incoming radiation (something which is also demonstrated by
> polarization).
>
> The double-slit experiment also demonstrates wave-like quality.
>
> If it looks like a wave, feels like a wave, smells like a wave, what is it?
> Not a wave, it seems. It just fakes being one quite well.
As I said, the probability of finding a particle in a particular place is
based on multiplying complex numbers. But since you never actually find a
wave, but only interference patterns (so to speak), it's probably not a
wave. The "wave" properties don't explain *all* the different kinds of
interference, but only the kinds that interfere like waves do. There's also
interference patterns that are the opposite of what you'd get with waves
(lasing vs exclusion principle) that is *also* explained by the theory in
which everything is a particle.
You really should watch the lectures (or read the book) I pointed you to.
They do a very nice job of explaining it. Both the video and the book are
Feynman, who got a nobel prize for figuring out how to explain to other
quantum physicists how to figure out wtf is going on with quantum mechanics,
so it's really quite interesting.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Warp wrote:
> Schrodinger's cat is a thought experiment, not an analogy.
It's not even that hard to set up. :-)
I think the point is that you have to question what an "observation" is. If
the particle gets emitted and runs into the detector when the power is
turned off, is it "observed"? If the power is on but the detector isn't
connected to anything? If it's connected to a speaker you can't hear? If
it's connected to poison but there's no cat in the box? Etc?
In other words, if it takes an "observer" to collapse the wave function, is
the cat enough of an "observer" to count? If so, how does the human get
involved? According to the math, the cat is still superimposed. But that
would imply the cat isn't sufficiently an observer to cause the collapse.
*Or* that the math doesn't match reality. And multi-worlds is an attempt to
say "no, the math really matches reality."
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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On 12/02/09 19:06, Darren New wrote:
>> I suppose that means that all phenomena caused by electromagnetic waves
>> (which light is)
>
> I think it's not considered to be an electromagnetic wave any more.
Throughout this thread (which I admit I did not read all of), you've
stated stuff a bit too definitively for my taste, as if all the top
physicists agree on this.
I can only abuse David Mermin's quote: "Shut up and calculate!"
I'm guessing that the actual mathematical formalism that we have for QM
addresses all that is _needed_, in that it always works, and we know of
no phenomenon (except perhaps gravity) that our mathematical formalism
fails at. Given that, having an argument about whether it's a wave or a
particle is philosophy of the pointless kind. The theory will remain
unchanged.
I'm truly baffled as to why y'all are arguing so much about this.
*Knowing* that it's a particle or a wave is not (as far as anyone
knows) going to change physics, or its rules, or even give better
results, or allow you to do better calculations. I'm not even sure if
any of you has bothered to *define* what a particle is or what a wave
is. Without doing so, the argument becomes even more amusing -
especially considering that what an electron/photon is may truly not fit
either one.
Which is likely the view I favor: Notions of particles and waves for
things like photons and electrons are somewhat meaningless Heck, a wave
was "meaningless" for light even before QM was known - what is it waving
in? I'm sure some of your (Darren's) arguments against viewing it as a
wave were as applicable in the 1800's, before QM came around.
Particles/waves, to me, are macroscopic phenomena. Photons and
electrons are described accurately by the mathematical rules in QM.
That's all there is. There's really nothing more to know about it. We
know as much as there is to know about QM as we did classical mechanics.
Ultimately, the latter was also properly described by a mathematical
formalism. We had an illusion that we understood that better merely
because we were used to it in our daily lives. But that's just an illusion.
(OK, I may be exaggerating a tiny bit in the last paragraph, but the
main point is that just because it seems "weird" doesn't mean it's any
weirder than classical mechanics).
>> as well as
>> exhibiting wave-like behavior such as polarization (how can you polarize
>> a particle given that polarization is by definition a property of waves
>> that describes the orientation of their oscillations?)
>
> Not in QM. I don't know too much about polarization, but it's not purely
> based on "wave" stuff.
In general, are you sure polarization cannot be described just by
waves? If you have waves in 3-D materials? FYI, the standard model for
sound waves in solids (i.e. phonons) assumes they have a polarization.
> You really should watch the lectures (or read the book) I pointed you
> to. They do a very nice job of explaining it. Both the video and the
> book are Feynman, who got a nobel prize for figuring out how to explain
> to other quantum physicists how to figure out wtf is going on with
> quantum mechanics, so it's really quite interesting.
I haven't read the book, but my physics professor said that it's THE
book to read (QED) if you want to get an understanding of light/EM
phenomenon.
--
Even if you win the rat race, you are still a rat.
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Neeum Zawan wrote:
> Throughout this thread (which I admit I did not read all of), you've
> stated stuff a bit too definitively for my taste, as if all the top
> physicists agree on this.
I'm just stating my understanding of the general consensus. I freely admit
that maybe they're wrong, but when the guy who got the nobel prize for
explaining to other theoretical pysicists how it works says "It's never ever
a wave", I'm gonna go with his explanation. :-)
> I'm guessing that the actual mathematical formalism that we have for
> QM addresses all that is _needed_, in that it always works, and we know
> of no phenomenon (except perhaps gravity) that our mathematical
> formalism fails at.
The other quantum stuff is similar but not identcail formulas, yes.
> Given that, having an argument about whether it's a
> wave or a particle is philosophy of the pointless kind. The theory will
> remain unchanged.
Yep.
> any of you has bothered to *define* what a particle is or what a wave
> is.
Well, I tried to indirectly describe things a wave would do that a particle
doesn't, but yeah.
> We had an illusion that we understood that better merely
> because we were used to it in our daily lives. But that's just an illusion.
True. It's like asking *why* there are three dimensions, or *why* you
subtract the square of time instead of adding it in GR.
> In general, are you sure polarization cannot be described just by
> waves? If you have waves in 3-D materials? FYI, the standard model for
> sound waves in solids (i.e. phonons) assumes they have a polarization.
I think the effect of polarization of quanta does stuff that polarization
based entirely on the directions of waves can't do, like lasing and fermion
exclusion.
> I haven't read the book, but my physics professor said that it's THE
> book to read (QED) if you want to get an understanding of light/EM
> phenomenon.
Yep. It's awesome, explained by the guy who invented the way to calculate
the stuff *based* on the explanation. The link to the videos is Feynman
presenting the lectures that got edited into the book, which is also
fascinating.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New wrote:
> In other words, if it takes an "observer" to collapse the wave function,
> is the cat enough of an "observer" to count? If so, how does the human
> get involved? According to the math, the cat is still superimposed. But
> that would imply the cat isn't sufficiently an observer to cause the
> collapse. *Or* that the math doesn't match reality. And multi-worlds is
> an attempt to say "no, the math really matches reality."
>
One tends to suspect that, as a thought experiment, it runs into the
same problem as Zeno's Paradox. Which is to say, there is some specific
minimum interaction/time frame/minimal distance, or what ever, in which
something either does *or* doesn't happen, and you can't have it be both
at the same time. In Zeno's case, there is literally a very small, but
provable, distance that you *must* move, if you move at all, and
crossing that line eliminates the paradox (in this case, probably
something like the closest you can get to another particle, without it
nudging the other particle, or something to that effect). They have
already proven, using QM experiments, that they *is* such a limit with
time, and that *before* that point you can nudge a particle back into
what ever state it had prior to measurement, but, anything after that
you are stuck with what ever the prior interaction gave you. The
previous assumption was that such events where instantaneous, and no
such micro-time event was possible.
Thus, the thought experiment is flawed, unless, as I said, you assume
that the entire box, everything in it, and thus what it does, is all
*one* object. A classic case of, "Of course a tree makes a sound if it
falls in an empty forest with no one to see it." The flaw is the
assumption that *someone* has to look into the box. I am not sure how to
put it.. Basically, its like astrology. Imagining that just because a
lot of big stuff is wandering around the universe, the small stuff
**must** be so drastically influenced by it that a cat can actually *be*
in such an indeterminate state. Not so. Either *any* interacting causes
a state change, in which case the cat *must* be in a known state
already, or nothing is, including the poor deluded fool worrying about
whether or not he killed the neighbors cat in the experiment, in which
case we might as well start talking to priest and gurus about
transcendentalism, and give up on physics.
Yeah, there are some goofy theories that sort of allow for it, but most
of them are notable in that they have to do things like throwing out
time, without having any damn math, never mind real theory, about how to
replace it with something that still *acts* like time from our view. Its
one thing to propose a thought experiment, its another to invent an
entire branch of, "this will fill in all the holes, I promise",
'science', which consists of no concrete data, experiments, theories, or
plausible mechanisms, and amounts to nothing *but* a long list of
thought experiments.
People tried that once before. It was called Alchemy, and, within its
own, flawed and incorrect, framework, everything known at the time
"worked" by its rules, including the math involved. It would be nice of
we at least tried to stick with dealing with the universe we can
observe, instead of wandering off into 50,000 of them we can't, trying
to find some weird sort of universe that would **look like** ours, if
stuck inside it. Not even string theory gets that odd, most of the time,
and it, so far, is about as useful at explaining anything as staring at
a something like the "accidental isosuface" thread is *actually* an
accurate method of predicting planet formation.
It might lead some place, maybe. At the moment, even some of the people
that wanted it to lead some place are looking at those studying the math
and thinking, "Ok, so... when are we going to get a theory, never mind
actual useful data, out of this 'science'?" lol
--
void main () {
If Schrödingers_cat is alive or version > 98 {
if version = "Vista" {
call slow_by_half();
call DRM_everything();
}
call functional_code();
}
else
call crash_windows();
}
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On 12/02/09 22:15, Darren New wrote:
> I'm just stating my understanding of the general consensus. I freely
The only real consensus is on the mathematical formalism. It wouldn't
surprise me if most physicists I've interacted would either say "acts
like both a particle or a wave, so it's both" or simply say "it's
neither, and don't waste time thinking about it".
Take the two Nobel laureates here:
"The 29 December 2005 edition of the International Herald Tribune
printed an article, "New tests of Einstein's 'spooky' reality", which
referred to Leggett's Autumn 2005 debate at a conference in Berkeley,
California, with fellow Nobel laureate Norman Ramsey of Harvard
University.[5] Both debated the worth of attempts to change quantum
theory. Leggett thought attempts were justified, Ramsey opposed. Leggett
believes quantum mechanics may be incomplete because of the quantum
measurement problem."
(From Leggett's Wikipedia page). His stance is interesting, as there
was another well known physicist (not a Nobel Laureate, but a member of
the NAS nevertheless) who argued that the derivation of the Bell's
Inequalities used arguments/theorems from statistics which, while
correct, were more limited in scope than most physicists think, and he
believed it wasn't sufficient enough to completely counter the notion of
hidden variables.
The "interesting" thing was that Leggett, who himself has issues with
the whole quantum measurement problem, thought this third guy was a
quack (on this topic, not as a physicist as a whole).
Physicists _do_ disagree. They probably only agree that it's
irrelevant.<G>
> admit that maybe they're wrong, but when the guy who got the nobel prize
> for explaining to other theoretical pysicists how it works says "It's
> never ever a wave", I'm gonna go with his explanation. :-)
Well, sure. And I don't doubt that many physicists including Nobel
Laureates disagree. And they're free to, because it is now in the realm
of philosophy. The theory won't change either way. I don't think any one
so far has come up with a "Well if we could show that it's REALLY a
wave/particle (whatever that means), then we'd have this phenomenon that
QM doesn't already predict".
I guess I mean to say that I doubt you can scientifically demonstrate
(i.e. with repeatable experiments) that it is truly a particle or truly
a wave or truly both. And if you did, I bet that you merely defined
particle/wave/both to be whatever the outcome of the experiment is.
>> We had an illusion that we understood that better merely because we
>> were used to it in our daily lives. But that's just an illusion.
>
> True. It's like asking *why* there are three dimensions, or *why* you
> subtract the square of time instead of adding it in GR.
Precisely.
>> In general, are you sure polarization cannot be described just by
>> waves? If you have waves in 3-D materials? FYI, the standard model for
>> sound waves in solids (i.e. phonons) assumes they have a polarization.
>
> I think the effect of polarization of quanta does stuff that
> polarization based entirely on the directions of waves can't do, like
> lasing and fermion exclusion.
Except that there's nothing fundamental in physics that doesn't allow
lasing with phonons instead of photons. God simply didn't give us solids
with the proper material properties that would allow it easily, and no
one has figured out a way to engineer such solids. See
http://en.wikipedia.org/wiki/Sound_Amplification_by_Stimulated_Emission_of_Radiation
The theory of phonons is almost identical to that of photons. Discrete,
energy packets of energy h*f, that can be absorbed/emitted by particles
like electrons. The math is quite similar. It's just that photons are
fundamental particles, and phonons, well, don't seem to be. They're just
atomic/ionic vibrations in a crystal lattice, and some kinds of phonons
are responsible for sound in solids.
Don't know what you mean by fermion exclusion. Maybe it was in another
message. You mean as in the Pauli exclusion? If so, I was referring to
photons and making the analogy, where Pauli exclusion doesn't apply.
PS - Apparently some people did claim to produce a phonon laser a few
months ago. I should try to see if I can make any sense of their paper...
http://today.caltech.edu/today/story-display-blurb?story_id=38363
--
Americans are getting stronger. Twenty years ago, it took two people to
carry ten dollars' worth of groceries. Today, a five-year-old can do it.
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Patrick Elliott wrote:
> Either *any* interacting causes
> a state change, in which case the cat *must* be in a known state
> already, or nothing is, including the poor deluded fool worrying about
> whether or not he killed the neighbors cat in the experiment,
Except that's exactly the point. The math says it's the latter case. And the
cat experiment is to point out how absurd that conclusion is. Hence, the
math must be mistaken.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New <dne### [at] sanrrcom> wrote:
> As I said, the probability of finding a particle in a particular place is
> based on multiplying complex numbers.
Btw, I find it curious how you use the mathematical models as some kind
of evidence that photons are not waves. After all, Feynman himself stressed
that his formulation is merely a mathematical description, not an attempt to
describe a real process that we cannot meassure.
--
- Warp
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > Schrodinger's cat is a thought experiment, not an analogy.
> It's not even that hard to set up. :-)
> I think the point is that you have to question what an "observation" is. If
> the particle gets emitted and runs into the detector when the power is
> turned off, is it "observed"? If the power is on but the detector isn't
> connected to anything? If it's connected to a speaker you can't hear? If
> it's connected to poison but there's no cat in the box? Etc?
> In other words, if it takes an "observer" to collapse the wave function, is
> the cat enough of an "observer" to count? If so, how does the human get
> involved? According to the math, the cat is still superimposed. But that
> would imply the cat isn't sufficiently an observer to cause the collapse.
> *Or* that the math doesn't match reality. And multi-worlds is an attempt to
> say "no, the math really matches reality."
AFAIK those are the things Erwin Schr?dinger questioned about the
Copenhagen interpretation with his now-famous thought experiment.
--
- Warp
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> As I said, the probability of finding a particle in a particular place is
>> based on multiplying complex numbers.
>
> Btw, I find it curious how you use the mathematical models as some kind
> of evidence that photons are not waves.
I believe you misunderstand me. I'm saying we never observe a wave. We just
observe math that's the same math as a wave. That isn't what makes it "not a
wave", that's what makes people used to think (and some people still think)
it was a wave. :-)
I.e., just the opposite. The mathematical model is *not* evidence it's a
wave, any more than the interference patterns are.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Warp wrote:
> AFAIK those are the things Erwin Schr?dinger questioned about the
> Copenhagen interpretation with his now-famous thought experiment.
Yes. I'm agreeing with you, and hopefully adding some more to the discussion.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Darren New <dne### [at] sanrrcom> wrote:
> I.e., just the opposite. The mathematical model is *not* evidence it's a
> wave, any more than the interference patterns are.
I don't really know your definition of "evidence", but as I understand it,
the interference pattern *is* evidence for it to be wave. It's not *proof* of
it, but evidence is no proof anyways.
--
- Warp
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> Except that's exactly the point. The math says it's the latter case. And
> the cat experiment is to point out how absurd that conclusion is. Hence,
> the math must be mistaken.
What happens if you shut the double-slit experiment away in a box, with
photon detector attached to each slit? Will the interference pattern still
be generated?
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scott wrote:
>> Except that's exactly the point. The math says it's the latter case.
>> And the cat experiment is to point out how absurd that conclusion is.
>> Hence, the math must be mistaken.
>
> What happens if you shut the double-slit experiment away in a box, with
> photon detector attached to each slit? Will the interference pattern
> still be generated?
No. Worse, check out this:
http://en.wikipedia.org/wiki/Wheeler%27s_delayed_choice_experiment
Basically, the photon behaves differently even if you measure it *after* it
has passed through the slits. Which is why it's pretty safe to assume it's
not "going thru both slits" when you get the interference pattern.
http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser
This one changes whether the photon went thru one or both slits *after* it
has already been detected. Hard to see how that's the behavior of a wave
that passes through both slits.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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>> What happens if you shut the double-slit experiment away in a box, with
>> photon detector attached to each slit? Will the interference pattern
>> still be generated?
>
> No. Worse, check out this:
>
> http://en.wikipedia.org/wiki/Wheeler%27s_delayed_choice_experiment
>
> Basically, the photon behaves differently even if you measure it *after*
> it has passed through the slits. Which is why it's pretty safe to assume
> it's not "going thru both slits" when you get the interference pattern.
But put the whole thing inside a big closed box so nobody can observe the
patterns (exactly like the cat in a box setup). If a cat's status is not
decided until someone looks inside (even though there is a particle detector
and related mechanisms inside) then why should the interference pattern not
be there if nobody is observing it?
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scott wrote:
> If a cat's status is not decided until someone looks inside
Since that isn't true, it's a meaningless question to ask.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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>> If a cat's status is not decided until someone looks inside
>
> Since that isn't true, it's a meaningless question to ask.
I thought the whole point of that experiment was that according to QM the
cat was both alive and dead until you actually tried to look? Maybe
something changed since I read about it?
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