Is the Moon there when nobody looks at it?

[Gerinski]

P.S. Upon careful consideration, I now think that as long as there is the tiniest probability of the Dow being under 10,000 on the specified day, the light will stay off. I am moving on to the next promising project that involves getting rich by using quantum states.

I think so too...

There's one more scenario for which I'm not sure of the answer:

If there's nobody in the lab to see if the light turns on or not, and it is not recorded in any way, I'm not sure if the light will lit on or not.
Since nobody is attempting to get any information of what happens in the pot, why should the atoms bother to collapse their superposition into any definite state? They might stay with a 0% - 100% superposition but without actually collapsing into the definite excited state?

 

[Sherlock]

The radiation shower is continuous, even while the atoms are being observed.

The observation is done by shining a laser beam through the "fog" of beryllium, and the scattering of the laser tells how many atoms were boiling and how many were not (because non-boiling atoms absorb some energy from the laser and boiling ones don't).

When observed, each atom can only be in any of either states, boiling or not-boiling, but nothing in between. They can only be in between (in a quantum superposition of both states) while not observed. This is the key.

During an unobserved 256 milliseconds radiation shower, every atom will evolve from a quantum superposition of states 100% not-boiling + 0% boiling, to a superposition of 0% not-boiling + 100% boiling.
At 128 milliseconds, the superposition is 50%-50%, at 64 milliseconds it's of 75%-25%, and so on.

When observed, each atom must abandon the superposition and "choose" between any of both states.

If you only observe after 256 milliseconds, all the atoms could get to the 0% not-boiling + 100% boiling superposition, so you find all of them boiling.

If you observe after 128 milliseconds, they are in a superposition of 50%-50%, therefore half of them will choose the non-boiling state and the other half the boiling state.

But for the 50% who take the non-boiling state, the superposition returns to 100% non-boiling + 0% boiling. Therefore they need again 256 milliseconds unobserved to evolve to 0%+100%, they have to start from scratch again.

Therefore if you observe them very repeatedly -every 4 milliseconds-, causing them to return to the 100% non-boiling + 0% boiling, they can never make it to boil even if the radiation shower is never stopped.

The interesting fact is that both the radiation shower (it is radio waves radiation) and the laser beam, are BOTH electromagnetic radiation being showered to the atoms. However the radio waves shower does not cause the collapse of the superposition, and the laser does. Why?

My guess would be that it has to do with the frequency of the
radio waves, the frequency of the laser light, and the resonant
frequency of the trapped beryllium ions.

Here's my take on the experiment from the link you provided:
If a beryllium atom is oscillating or resonating
due to excitation by a certain radio wave
frequency when light from a laser pulse hits it,
then the chance of it scattering the light from the
laser pulse back to the detector is very small.

It takes about 256 milliseconds for the radio waves
to get most all of the 5000 beryllium ions in the
electromagnetic trap resonating.

On average, if left undisturbed, about 19.5
atoms (or .0039% of the total) are added to the
resonating group each millisecond.

The atoms that are resonating stop resonating
after interacting with the laser light. During any
particular 2.4 millisecond pulse virtually all the atoms
that are resonating will stop resonating.

If you hit the beryllium atoms with 64, 2.4 millisecond
laser pulses at regular intervals during a 256 millisecond
run, then there's about 1.5 milliseconds between each
pulse for a certain number of atoms to resonate
again -- which would be a barely detectable percentage
of the whole group.

The longer the interval between laser pulses, the fewer atoms
will be directly detected as not resonating -- and then this is
subtracted from the total in the trap to get the percentage of
atoms that are resonating (or 'boiling' re the 'watched pot'
metaphor) wrt a particular delta t.

The only difference is that we use the laser to observe, while we don't with the radio waves. We look at the laser scattering to get information on which is the state of the atoms. Presumably, if we used the same radio wave shower to get that information, they would also never boil.

I don't think you can use radio waves to get that info.
But, I'm not sure about that.

Therefore it seems unavoidable that it's our getting knowledge of the world what makes it be like it appears to us. This is the deep dilema (and personally I don't like it. I don't like to think that we are so special)

This isn't really so perplexing the way you're stating it, is it?
I mean, of course the parameters of our physical existence
determine what we apprehend and how we apprehend it.
This by itself makes us no more special than any other
measuring device.

 

[Sherlock]

Let's imagine that you could set up the device so that when all the atoms get to the excited state (boiling), a red light is lit on the lab wall. I have no idea how to do it, but all being hypotetical let's imagine that non-excited beryllium was non conductor and excited beryllium became superconductor, allowing when all of the atoms are excited to let through just enough electrons to lit the light.
The light is in fact an observation device, but able only to observe when ALL of the atoms are boiling, we can't observe anything in between until then.

Now guessing:

1. If we don't shine laser at all, after 256 milliseconds the light will lit on (the fact of letting the atoms reach the 0% - 100% superposition state will be enough to collapse them on the boiling state and lit the light, because we have set up the light in order to be able to observe that event)

Yes, the 'pot' will be 'boiling' in this case, but not because you
set up the light to record the result. The red light isn't
the measuring device. The laser light is.
It takes at least 256 milliseconds for all of the trapped atoms
to resonate. So, if you don't zap them with the laser for the
duration of a 256 millisecond run, then your detection light
will light. And, if you didn't set up the detection light, they'd
still all be resonating after being exposed to an appropriate
radio frequency for 256 milliseconds. At least, that's the
assumption that I'd make.

2. If we shine the laser every 4 milliseconds and watch the scattering result (acquiring information on the state of the atoms), the light will never get lit (because we are continuously bringing back all the atoms to their starting 100% - 0% superposition state).

Yes, the light won't light in this case, but here's the
reason I'd give:
The non-harmonic (I'm guessing) interaction of the laser light
with the trapped ions effectively destroys the resonance
created by the radio frequency.

3. If we shine the laser every 4 milliseconds but do not watch nor record in any way the scattering result, the light will lit on after 256 milliseconds (just as if we did not shine the laser at all, because we can't get any information)

No. The laser light stops (interferes destructively with)
the 'boiling' process.

4. If we shine the laser every 4 milliseconds and do not watch the result, but record it so that we could watch it later on, the light will never lit on (because information can eventually be retrieved from the recorded data)

Yes, in this case the light won't light -- because you've zapped
the atoms with a 2.4 millisecond laser pulse every 4 milliseconds.

I'm not 100% sure that I'm right but I guess so. Weird ...

Well, as you can see, I don't think it's so weird. But,
I could be missing something.

 

[RonLevy]

Quantum Weird - Want more!

These Quantum Theory "weird" experimental results and strange implications of theory are a striking feature of this branch of science. Would any of you be able to contribute your own paradoxes and points?

 

[Gerinski]

The atoms that are resonating stop resonating
after interacting with the laser light. During any
particular 2.4 millisecond pulse virtually all the atoms
that are resonating will stop resonating.

Hi Sherlock. Your understanding of the experiment is wrong and therefore you miss the quantum aspect.

The laser does NOT in any way bring back excited atoms to the unexcited state (I believe excited is a more appropiate word than resonating, although it doesn't matter).
This is clear, if you shine the laser after 128 ms, you find 50% of the atoms excited, and these will remain excited. This 50% do NOT go back to the unexcited state. The proof is that if you measure shortly again, you will find more than 50%, never less.
Only the 50% which "choose" to be unexcited will remain unexcited (for these, it's not that they "go back" to unexcited, because they were never excited. They just had a certain probability of being excited (actually 50%) and it's this probability which returns to zero).

What the laser does is just to "force" each atom to define its state as either unexcited or excited, and which one the atom will take is defined by the probability % quantum superposition of both states.

What the laser does (e.g. if fired at 128 ms) is to take the group of atoms, which are all of them in a state of 50% probability of being unexcited + 50% probability of being excited, and split them in 2 groups, one of them with a 100% probability of being unexcited + 0% of being excited, and the other group with a 0% probability of being unexcited + 100% of being excited.

You can not explain the experiment results without resorting to the quantum superposition of states (atoms must be in 2 different states simultaneously) and to the incompatibility of observation with this superposition (we can not observe this superposition, observation collapses the superposition into any of the definite states).

Quote:
Originally Posted by Gerinski
3. If we shine the laser every 4 milliseconds but do not watch nor record in any way the scattering result, the light will lit on after 256 milliseconds (just as if we did not shine the laser at all, because we can't get any information)

No. The laser light stops (interferes destructively with)
the 'boiling' process..

I'm not so sure. Other experimental setups, such as the "delayed choice double-slit experiment" and particularly the variant with the "quantum eraser" have proved that it's not the fact of putting an interacting detector or not what defines the result of an experiment, but wheter we can extract any information or not from that detector. Exactly the same setup with the same detectors yield different results if we are attempting to learn the result or if we are not.


Maybe this discussion has become ortodox enough for the moderators to bring back this thread to the Quantum Physics forum, where more expert people could clarify our doubts ...

 

[Sherlock]

Hi Sherlock. Your understanding of the experiment is wrong and therefore you miss the quantum aspect.

The laser does NOT in any way bring back excited atoms to the unexcited state (I believe excited is a more appropiate word than resonating, although it doesn't matter).
This is clear, if you shine the laser after 128 ms, you find 50% of the atoms excited, and these will remain excited. This 50% do NOT go back to the unexcited state. The proof is that if you measure shortly again, you will find more than 50%, never less.
Only the 50% which "choose" to be unexcited will remain unexcited (for these, it's not that they "go back" to unexcited, because they were never excited. They just had a certain probability of being excited (actually 50%) and it's this probability which returns to zero).

What the laser does is just to "force" each atom to define its state as either unexcited or excited, and which one the atom will take is defined by the probability % quantum superposition of both states.

What the laser does (e.g. if fired at 128 ms) is to take the group of atoms, which are all of them in a state of 50% probability of being unexcited + 50% probability of being excited, and split them in 2 groups, one of them with a 100% probability of being unexcited + 0% of being excited, and the other group with a 0% probability of being unexcited + 100% of being excited.

You can not explain the experiment results without resorting to the quantum superposition of states (atoms must be in 2 different states simultaneously) and to the incompatibility of observation with this superposition (we can not observe this superposition, observation collapses the superposition into any of the definite states).

...

I'm not so sure. Other experimental setups, such as the "delayed choice double-slit experiment" and particularly the variant with the "quantum eraser" have proved that it's not the fact of putting an interacting detector or not what defines the result of an experiment, but wheter we can extract any information or not from that detector. Exactly the same setup with the same detectors yield different results if we are attempting to learn the result or if we are not.

Maybe this discussion has become ortodox enough for the moderators to bring back this thread to the Quantum Physics forum, where more expert people could clarify our doubts ...

I found a link to the Itano et al. experiment as well as another
paper that might help us. Haven't had time to read them yet.
I suggest keeping this thread here and maybe starting another
one on interpretations of the quantum zeno effect in the
quantum physics forum. But, first I'd check in the archives
and the faq and the journals of the advisors and mentors to
see what's already been said here about it. (I haven't had
a chance to do this yet either.)

http://en.wikipedia.org/wiki/Quantum_Zeno_effect

Experimentally, strong suppression of the evolution of a quantum system due to environmental coupling has been observed in a number of microscopic systems. One such experiment was performed in October 1989 by Itano, Heinzen, Bollinger and Wineland at NIST. Approximately 5000 9Be+ ions were stored in a cylindrical Penning trap and laser cooled to below 250mK. A resonant RF pulse was applied which, if applied alone, would cause the entire ground state population to migrate into an excited state. After the pulse was applied, the ions were monitored for photons emitted due to relaxation. The ion trap was then regularly "measured" by applying a sequence of ultraviolet pulses, during the RF pulse. As expected, the ultraviolet pulses suppressed the evolution of the system into the excited state. The results were in good agreement with theoretical models.

http://tf.nist.gov/general/pdf/858.pdf

(NOTE: if this link doesn't work, then just go to the parent
directory http://tf.nist.gov/general/pdf/
and scroll down till you find the link for 858.)
_____________________

Quantum Physics, abstract
quant-ph/0105138
From: Julius Ruseckas [view email]
Date: Mon, 28 May 2001 12:18:36 GMT (69kb)

Real measurements and Quantum Zeno effect
Authors: Julius Ruseckas, B. Kaulakys
Categories: quant-ph
Comments: 3 figures
Journal-ref: J. Ruseckas and B. Kaulakys, Phys. Rev. A 63, 062103 (2001)

In 1977, Mishra and Sudarshan showed that an unstable particle would never be found decayed while it was continuously observed. They called this effect the quantum Zeno effect (or paradox). Later it was realized that the frequent measurements could also accelerate the decay (quantum anti-Zeno effect). In this paper we investigate the quantum Zeno effect using the definite model of the measurement. We take into account the finite duration and the finite accuracy of the measurement. A general equation for the jump probability during the measurement is derived. We find that the measurements can cause inhibition (quantum Zeno effect) or acceleration (quantum anti-Zeno effect) of the evolution, depending on the strength of the interaction with the measuring device and on the properties of the system. However, the evolution cannot be fully stopped.

http://arxiv.org/PS_cache/quant-ph/pdf/0105/0105138.pdf

 

[Gerinski]

These Quantum Theory "weird" experimental results and strange implications of theory are a striking feature of this branch of science. Would any of you be able to contribute your own paradoxes and points?

As I-don't-remember-who said (was it Feynman maybe?) the whole wonder and paradox of the quantum world is encapsulated in the double-slit experiment.
Indeed, starting from such a simple experiment with a beam of light, a perforated panel and a screen, as scientists have gradually progressed in observing and interpreting what happens (and especially after introducing refined versions of the experiment such as the delayed-choice and the quantum-eraser), nearly all the mysteries and weirdness of the quantum world unfold in front of your eyes.

This is the thread line that most popular science books follow, but it's too long to describe properly in a place like this.

The best would be that you get some good popular science book/s (as the layman I am, I particularly liked John Gribbin's "In search of Schroedinger's cat" and its sequel "Schroedinger's kittens". David Deutsch's "The fabric of reality" is also great, although very biased in the interpretation of quantum theory towards his favourite "multiverse").

 

[jimmie]

is the thread

Is the Moon there when nobody looks at it?

there when nobody looks at it?

you know its there if nobody looks at it because you witnessed it being put there by its creator--you.

all that is needed to confirm the true "presence" of anything created "is" an impartial, non-biased, objective, non-action witness.

if you would like to go a little deeper, the "Moon" is always in motion, so when you ask "Is the Moon there?", what "there" are you referring to? The presence of the Moon being anywhere, or an exact location in orbit to where the moon was, or shall be?

An answer to the latter can be found, I speculate, at NASA.
An answer to the former can be found, I know, "in here". (I/you)

 

[mandril]

I would like to give a sort of personal view (founded in interprtation of modern philosophy) about this issue, that I am developing for a work to get a degree in physics. I belive, that the whole problem has to do with the fact that our mesurments are so precise that we have to give up some "classic" notions about, not the actual existence of reallity (denying its existens would be, at this point absurd) but the way it exists. We can no longer hold the view that we can have any konwledge of "absolute" reality without interacting with it. That is, in case independent reallity exists, it makes no sense talking about it, and as Wittgenstain use to say "Of that which we can talk about, the best thing to do is keep silent" What we can talk about is "conceptually designated reallity" (The book "Choosing Reality" by Alan Wallace is grate to explain this point), and for that we have to accept that separation between observer and object was an ilussion, in the first place. If anyone is interested in book or references about the philosophical aspect, I would be more than happy to help.

 

[-Job-]

If a particle doesn't have a definite position until observed, but is in a "superposition of positions", then why is it that the result of an observation is dependent on the position where the observation is performed. If a particle does not have a definite position, why is it that I'm more likely to, upon observation, find a particle in a given position and never in another.
For example, say that i know that a particle came into my room, but i don't know exactly where it is. Suppose i make an observation on a randomly chosen portion of the room, to check whether the particle is there. There is a positive probability that it is in the area i chose. The bigger the area i choose, the bigger the probability that the particle is there. But consider that i search outside the room. I'm 100% sure i saw the particle come into my room, that means 0% probability that it's not in my room. So the particle is in a superposition of positions because i don't know where it is, but does it mean that it is in a superposition of the positions available inside the room, or in a superpositions of all available positions in the universe? Certainly i can imagine the particle could have traveled outside the room, and so it's a non-zero probability that the particle is outside the room. But certainly there are positions outside the room where the particle cannot be. The particle having entered my room, could not have traveled at the speed of light to 1 billion miles away, in less than X minutes. therefore i can send a signal traveling at the speed of light to a friend of mine who will verify whether or not the particle is 1 billion miles away. But, of course, the particle couldn't possibly be there, it would be against the laws of physics. So it seems to be that a particle that has entered my room is not in a superposition of all possible positions in the universe, but only a given subset.
Having said that does it mean that, if i saw the moon a minute ago, even though i don't know where it is now, it certainly cannot be next to Pluto, because it couldn't have gotten there.
How can we even distinguish particles? Atomic, subatomic particles. If we can't distinguish the particles then what use is an observation? When measuring the spin of a particle, how do i know that some other particle didn't get in there, and it's that particle's spin that I've measured?
Suppose that i look for my particle outside my room and i meet a particle that's exactly like it. How do i know if it is or isn't my particle? If it is and i think it is then how does my observation change the world? If it isn't and i think it is, does my observation change the world in the same way?
Suppose I'm always able to distinguish my particle. Doesn't that imply hidden variables? I mean after all, that would imply that no other particle is like mine and does not have the same properties as my particle, which already says something about every other particle, namely, that it is not like my particle.

One alternative is that you can make an observation, and have an impact on the universe, but not know what the impact was. So it doesn't take a conscious being to make an observation, because you wouldn't be conscious of the result anyway. And then inanimate things, like a rock,can make an "observation". It can "observe" the position of another rock by hitting it. Then, what that means is that when rock A hits rock B, it causes rock B to have a definite position. Suppose i never saw one rock hit another. Supposedly rock B should not have a definite position, but rock A made sure it did, regardless of whether anyone made an observation; hidden variable.

 

[quantumcarl]

I used the moon as an example to illustrate the same question in the Quantum Physics Section of PF.

If no human has observed the moon or been able to calculate its existence through studying its physical effects... does the moon exist under the terms and formulations of quantum mechanics?

this got quite a few replies from some excellent sources on PF not unlike this thread!

Here's the thread:
https://www.physicsforums.com/showthread.php?t=106188

 

[scott1]

I did a google search and I found this article
http://www.ruf.rice.edu/~hpu/Phys311_source/mermin_moon.pdf