Problem with the Cat:

Actually, you got the point - which many people seem to miss.

Schrödinger proposed the dead-cat/alive-cat thought experiment as a criticism of the Copenhagen Interpretation of QM. He thought the idea of such superpositions of states as absurd and the cat-in-the-box idea was his way of pointing out this absurdity.

Alas for Schrödinger -- like Fred Hoyle's nickname 'The Big Bang' for a cosmology he thought was absurd -- the idea stuck. Most physicists now use Schrödinger's Cat as an example of the concept of superposition, rather than as the criticism Schrödinger intended.

I am aware that Schrodinger meant his thought experiment to be an illustration of the absurdity of quantum theory, but as you stated, many physicists consider it to be factual, not a parody of superposition.Still , the absurd appears to happen in the quantum world,and superposition is accepted as a valid state.This tends to deflect study of the real reasons for this illusion.If we accept that superposition does not occur, that frees us to search for the real reasons of this effect.

Bravo to you both.

I wish I could elaborate in better detail to help solve this apparent effect but the uncertainty of this cat seems to be either a desired paradox of quantum mechanics or if the cats status in quantum mechanics terms just cannot be clarified until observation.

One thing that I can elaborate a little about this effect is that a key part of this thought experiment is trying to demonstrate is how quantum mechanics handles the vector of time. Until one adds the event of an observation one cannot discern which direction time is traveling. Prior to observing the status of the cat and getting the alive or dead cat out of the box one has an unknown status of the cat. Having an alive or dead cat and going backwards in time you do not go back to the unknown cat status.

Related to this quantum mechanics paradox is the topic of entanglement that just baffles me. I've asked a few of the applied physicists that I work with to explain entanglement to me. I just don't get it. I might post a new thread on my limited understanding of entanglement and why I think that this is a case that just seems like folly to me. Maybe somebody here can set me straight.

I've read some books by the Oxford mathematical physicist Roger Penrose, who does a very good job of explaining a lot of this stuff. The link below is to a YouTube video from a number of years ago where he discusses QM and includes a wonderful discussion of the Schrodinger's Cat problem using an overhead projector and some handmade slides. I wish the video had gone longer because at the end he discusses his alternative viewpoint to the Copenhagen and Many Worlds interpretations. The video is about 25 minutes long, with the Cat problem discussion starting at about the 12:30 mark - though I recommend watching the discussion beforehand that leads into the Cat discussion.

http://www.youtube.com/watch?v=0fXfh-IFMSs

Dissenting opinions you won't have much, at least not from honest people who don't pretend to be experts in the matter.

Have you heard the stupid question of the falling tree in the middle of a forest, with no one to listen...? well, it does make a sound, just go there the day after and ask local squirrels, even if you don't care going there they'll be commenting it.

About time, I think time is not a vector or any measurable parameter for the matter, it is a reference we invented to measure the effects of natural fenomena and make accurate predictions.

The whole universe is just energy transfer and matter decay.

"Have you heard the stupid question of the falling tree in the middle of a forest, with no one to listen...?" No, but I've heard a rather subtle question quite like it.

Before you answer this "stupid" question so confidently it helps to understand the reason it was asked, look at the "If a tree falls.." wiki and read a bit on the history of western philosophy.

We don't know the truth here, we just guess and then try to prove it....Each time we gain some observable phenomenon we modify our guess, and go on trying to prove that....In this journey to understanding, we come to some weird places, and indeed the universe and reality might just be the weirdest of all in the end....

I absolutely agree, I just tend to strip all I can, to its most simple form and then judge it with simple common sense (a tiny little place where no cats are allowed).

Regards

IMO, more important than the specifics of the cat-in-the-box analogy is the fundamental concept of objective/subjective science.

Think about the basic measurements made everyday by various people... the op-amp in the digital multimeter reading a voltage, the pressure gauge reading in a piping system, etc. These measurements in the strictest sense affect, however slight, the parameter they attempt to measure. When doing cicuit analysis, the resistance of the voltmeter is not actually infinite, but some large finite value taken as infinte ease of calculation. In a practical sense, such as for an engineer, this is fine because it doesn't change the magnitude of the result in any practical way, but the act of measuring does change the system.

Speaking to the cat... One professor I had switched up the analogy to make it a bit more easy to swallow. He said imagine an opaque cup (like a Yahtzee cup) and a mechanism that will roll a die for us when covered and uncovered by the cup. Put a die in, take the cup and cover the machine. So our die is now rolling. So our die is stuck mid roll. How do we describe the die? Is it a 1, 2, 3, 4, 5, or 6? Is it all of them? In a sense it is all of them and everything in between. We know that once we lift the cup, the die will land in one of those positions, but it isn't until we do that the actual roll is determined.

I liked it better than the cat.

I can think of at least two measurements which don't represent a load to the parameter being measured: Pyrometry and IR imaging.

About the die, the rotation of the same doesn't blend all faces, edges and aristas into one thing, or it would become a sphere; the exact position of the die can be calculated at a given time knowing the mechanics of the machine.

But this is just my opinion, after all we all perceive reality in diferent ways, or there wouldn't be any geniuses throughout the mankind history.

Actually even in those two cases, the act of measuring does change what is being measured. However, the anticipated change is less than the uncertainty of the measurement so it is typically ignored.

The pyrometry and IR imaging cases you mention are for macro objects. Your detector interacts with the emitted photons and once you observe those photons you have changed their quantum state.

...similar to what redfred said.

Actually in the spinning die case it is an illusion that one can precisely predict the trajectory and spins that a die can take. All of the measurements of the velocity vector (magnitude and direction), angular spin rate, any drag coefficients, etc. that will determine the dies final position for a classical mechanics prediction will all have uncertainties in their measurement.

The problem with the fate of the cat is determined by Heisenberg uncertainty principle. Electron spin is one example of that problem and it was verified by the Stern-Gerlach expirement. The Dirac wave equation takes into account time and it's very beautiful . The cat's fate is included but it's the time factor that we tend to forget. People hate probabilities and quantum mechanic is based on it.

" ... the exact position of the die can be calculated at a given time knowing the mechanics of the machine. While true in the spinning die example, in the quantum world this would violate the Heisenberg uncertainty principle."

Not true even in the case of the spinning die example. Why? 'Knowing the mechanics of the machine' to the level of detail necessary to predict the outcome with absolute certainty at a given time requires absolute knowledge of the 'mechanics of the machine' and of its entire history at the quantum level. That knowledge is forbidden, again by the HUP, because the level of detail required to make such a determination brings us right back into the realm of QM.

-e

When it is said that the result is not fixed in reality until it is observed, are we not simply saying that we cannot know something before we know it?Until we are conscious of it?Aware of it?

We can see nothing except the past. A photon bouncing off of an object is delayed slightly by the travel time to our eyes from the object, as well as the processing time of our visual system.No matter how close we get, there is a delay.We are always lagging behind reality.Reality is the only thing that happens in 'real ' time,and we cannot see or perceive that.We are always lagging behind reality.The condition of the cat is fixed in reality.The perception of it's state cannot be known until we observe it,and that is always a step after(whatever) happened.So, unless a future event can affect a past event,the observer has no effect on reality.This violates the time arrow, does it not?

"... are we not simply saying that we cannot know something before we know it? Until we are conscious of it? Aware of it?"

Depends on 'it'. In the case of two entangled photons, for example, we can know the state of the unmeasured photon by measuring the state of the other. But what is meant by superposition goes well beyond simply knowing or not knowing the state of something prior to measuring it. Why? All else being the same, a stream of (un-entangled) particles each measured in exactly the same way, for example, are unlikely to give identical results regardless of how much else we know about them beforehand. It is not enough to say that we don't know, it is that we cannot know - not even in principle.

-e

"are we not simply saying that we cannot know something before we know it? Until we are conscious of it? Aware of it?"

Dwell on that statement for a while, and you will see that I am saying the same thing, without the smoke and mirrors of QM.(Not that all of QM is smoke and mirrors). We cannot know the state of anything until it is measured, no matter how much or little we measure, and it is the state of knowing that brings it from the world of probability into our world of reality.

Did you know that the photons were entangled before the measurement? If so, then you already know enough to determine that the other half of the pair will be affected by default.

What if you didn't know they were entangled? You would know nothing of it's partner on the other side of the universe.It would appear to be a solo un-entangled photon.

As large as the universe is, and as small as a photon or electron is, there are plenty of un-observable places for them to be.Or not to be.

Help me clear my head on this.

Sorry, I neglected to mention that a measurement of the state of one member of an entangled ensemble (of, say, photons) is a measurement of the state of the ensemble as a whole. Quantum entanglement results in a system whose aggregate state can be known by measuring one of its components (very convenient!). In accordance with QM, prior to measurement the entire system exists in a superposition of states. In this sense it behaves no differently than an individual un-entangled object.

Where the idea of entanglement collides head-on with conventional wisdom is that QM places no bounds on how the system is physically distributed throughout spacetime. Moreover, QM says nothing about how the various pieces 'communicate' nor even if they do (nor even if the idea of 'communication amongst members' itself has any meaning whatsoever).

For example, let's say we have two photons travelling through the Universe in opposite directions and have been for the last 13 billion years or so. They somehow got entangled about 300k years or so after the Big Bang, right after the primordial fireball cooled enough to become transparent to light.

Now, let's say one of the pair arrives at Earth just in time to have its polarisation measured by an astronomer. What happens to the other, unmeasured photon at that instant? Anything? Oh yes! Because they're entangled, the other photon's polarisation will be immediately established at that moment. It matters not that the unmeasured photon happens to be 'on the other side of the Universe' at the time. Why not? Because what was measured was not the state of one photon, but the aggregate state of the system as a whole.

The unmeasured photon 'knows' its polarisation now not because this knowledge was somehow communicated superluminally from afar, but because, being intrinsically bound with the quantum system of which it is a part, it has no choice but to assume the identity representative of the system as a whole AND at the very instant that state is determined. The wavefunction of the of ensemble is what collapses, not the wavefunction of a single, entangled photon.

In general it may be said that, insofar as the state of an ensemble is concerned, there are no individual components. The wavefunction is of a single object, ie, of the system as a whole and that is what is being measured. Communication is necessary only if two more objects are involved, but that is not the case here. Here we have one quantum object and in this context the idea of communication amongst members not only does not occur, but the concept itself is meaningless. Where there is entanglement, the measured state is that of a single system.

-e

I mentioned earlier in this thread that I had some "issues" with entanglement. I did intend to start another thread on the topic but since the topic has been brought up here I'll pose my concerns here.

I understand and like the provided definition that two particles can become entangled and that each becomes a "balanced pair" of really a single system. My issue is that these two parts of this one system get separated and will interact with different parts of the universe. One photon may collide with the vacuum chamber wall, while the other photon sails down to the experiment measurement device and be tallied in one quantum value or another. Part of this system has been destroyed or more accurately been converted into another form of mass/energy and no longer retains the assumed balanced entanglement with the detected particle. Now one can easily set up an experiment so that the particles detected at location A should have their compliments at location B at the moment of detection. For entanglement to provide an accurate tally of the particles reaching point A there seems to be a few unstated assumptions in the process. All particles detected at A are particles created by the entanglement process. No entangled particle reaching A or B interacts with any real or virtual particle in transit.

If either particle interacts with the environment prior to measurement, all bets are off. We're no longer measuring an entangled system and the question of what we're measuring becomes moot.

Fortunately the chances of observing 13-billion-year-old entangled quanta are pretty good. Why? Because the chances of observing 13-billion-year-old quanta are in general pretty good. If they weren't we wouldn't be able to measure the CMB as well as we have for instance. If all those photons which comprise the CMB had interacted with their environment along the way (apart from being 'stretched' en route as the Universe expands), we'd never see them. But we do see them. Thankfully the Universe is as highly transparent to EM radiation as it is.

There are some links I'd like to post here but I've got to find them first and it's been a long, difficult day and I'm ready to hit the hay. See ya manana.

-e

I have been annoyed when I read books that raise the entanglement subject and then say that it cannot be used for communication but go no further, no examination of systems and explanation of why not.

If we wish to communicate with a star, say, 10 light years distant and we set up a source of entangled pairs, equidistant from earth and them, and aimed towards both of us, we should be able to have instant communication by making them pass through a polarized lens', making their axis vertical or horizontal. A preponderance of verticals could mean "0", and a majority of horizontals could mean "1", a balanced flow meaning there is no message content at that moment.

A polariser transmits or blocks photons depending on their polarisation, it does not assign it. As the polarisation of the entangled pairs is both random and unknown prior to measurement, their polarisation as measured at either end will be likewise random.

Let's kick around this idea if you like: Let's say we have an emitter of entangled pairs at the midpoint, as before, but this emitter periodically varies the polarisation (which can be controlled at the source) according to some agreed-upon schedule. To keep things simple, let's assume the schedule corresponds to a fixed-frequency square wave: we emit one polarisation p0 for an interval t1, then the other polarisation p1 for an interval t2, then p0 for t1, et cetera.

Now, in order to transmit a message to Planet Bob (B), Planet Allice (A) passes its end of the photon stream through (say) a Pockels cell, which lets (A) either rotate the polarization or not according to the message content. (A) subsequently 'measures' the stream by passing it through a polariser thus fixing the polarisation of the stream (B) is receiving so that in the unmodulated case, where (B) would expect to see p0 it measures p1, and so knows that Alice flipped the polarisation at her end. Same with the other polarisation. Sound good so far?

Now, what is the fatal flaw in this scheme? The one that prevents information from being transmitted in this way? (superluminally no less)

-e

First, we must get rid of the cat, the cat is only a, non-quantum, flag to tell us if the, quantum, uranium atom radiated a particle, the uncertainty is the state of the uranium atom. If we simply had a detector instead of the cat, few would argue. I imagine that it is useful or convenient to think of the cat, or the detector, in the same superposition state as the atom. I resisted the whole ball of not knowing until I read everything I could find on the two slit experiment, then I capitulated.

From: http://phys.wordpress.com/2006/06/09/quantum-mechanical-quotes/

• Those who are not shocked when they first come across quantum theory cannot possibly have understood it. Niels Bohr.
• If you are not completely confused by quantum mechanics, you do not understand it. John Wheeler.
• It is safe to say that nobody understands quantum mechanics. Richard Feynman.
• If [quantum theory] is correct, it signifies the end of physics as a science. Albert Einstein.
• I do not like [quantum mechanics], and I am sorry I ever had anything to do with it. Erwin Schrödinger.

There are 2 cats in the box, one dead and one alive, and these cats have the ability to pass the alive property from one to the other.

Did I also say dead cats are weightless?

In particle physics, where the cat is properly located, things work out differently from our macro world. There the cat is alive AND dead (probability) until an observation decides which.

There is a simpler version of the same. You send a photon thru a christal, that split it in two, sending it this way and that. When this is measured here, as of sudden that is determined there. It is spooky, counterintuitive. Also, it was tested repeatedly.

Does that violate your sensibilities? Welcome to the Alice Wonderland of particle physics.

A full size cat? It simply IS alive or dead, even if you do not look.

Cat say, only exist in dream of dog...

Excellent question, HTRN, but not in the least bit easy to answer to any degree of satisfaction, and the ramifications are many and varied. You may find this article especially enlightening, for starters. For one thing it shows that, at least in principle, interaction-free measurement is indeed possible (your question boils down to the quantum measurement problem and the dichotomy between the macro world in which we live and the bizarre and mostly counterintuitive world of the Very Small). All of the links here in my response bear on your question in one way or another. No promises that this will be easy - or hard.

Other links which you may find of considerable interest (especially the ones discussing quantum decoherence, a proposition (see also) that it is an unnecessarily restrictive and complex solution to the quantum measurement problem, and the demonstrably counterfactual* nature of QM, ie, CFD):

Seven Wonders of the Quantum World (New Scientist. Interesting but not rigorous)

Steven Weinberg: Einstein's Mistakes, Physics Today, http://physicstoday.org/journals/doc/PHTOAD-ft/vol_58/iss_11/31_1.shtml?bypassSSO=1 (Sorry, link no longer available!)

Renninger Negative-Result Experiment

Decoherence, the measurement problem, and interpretations of quantum mechanics (pdf)

Collapse Theories

The Role of Decoherence in Quantum Mechanics

Decoherence (website)

Decoherence and the Appearance of a Classical World in Quantum Theory (Google eBook)

The Mott Problem (paradoxes involving wavefunction collapse)

Quantum Entanglement

The EPR (Einstein-Podolsky-Rosen) Paradox

Bell's Theorem / Bell's Inequality

CHSH Inequality

Principle of Locality

Quantum Entanglement and Information

This list is by no means complete, as you might imagine. One thing to keep in mind. The observer is instrinsically part of the QM system being observed. We're not Classical Observers in a quantum universe, we are intrinsic to it, and that my friend defines what we observe (and do not observe). Once we make a measurement, we become entangled with the system we are observing in every sense of the word. It is why, IMHO, we see the world as being Classical. A natural consequence of entanglement as we perceive it. There is no Classical Universe and it is a mistake to believe otherwise because the concept introduces an artificial dichotomy between the Observer and the Observed that cannot exist once the measurement is made.

-e

----

* One of the more counterintuitive implications of CFD is that the result of a classical computation can be obtained without actually carrying it out (but will take as long to get even so) given only that the potential for performing the calculation exists.

That is certainly a lot of grist for the mill, but I will grind away at it diligently.Whether the results will be digestible or not is a different matter.

Everything we know about reality is based on our awareness of it, obviously.Nothing is totally real till we observe it, so in that sense, everything is in that gray twilight between dream and reality until we are conscious of it.

On an individual level, we create our own reality.No one else can do that for us.We can only truly know that which we experience first hand, so in that sense, everything is subjective.

As I stated previously, we are observing quantum events as they were in the past, not the present, so the event, whatever it was, has already occurred before we observe it.We are always a little behind "real" time because of the speed of C.No observation can exceed the speed of light, and there is always some distance between an observer and the event,therefor a delay.

A good illustration is a baseball game.A good base referee will look at the base, and listen for the sound of the ball hitting the baseman's glove to decide if the runner is out or safe.A fan sees the same event from a distance, and disagrees with the referee, because he saw the runner touch base before he heard the ball hit the glove.Both are correct, from their point of view and a video/audio recording from each location would prove opposite results.Both results are true, the perspective is different.The ref is closer to the action, so his experience is closer to objective reality.In a baseball game, C does not matter much, but the speed of sound vs the speed of C has caused may arguments between fans and referees.

Such is the quantum world, IMHO.There is a always a delay.The closer we get to the object observed, the less delay, but a delay nonetheless.How long does it take light to travel a Planck length? Our observation of the event does not affect the outcome, rather the outcome affects our observation of it.

It is what it WAS.

If there were some way to exceed the speed of C, we could have a true instantaneous measurement, but then we would have to process the information faster than C to have meaning.

This is getting into the realm of the "dream of the butterfly" now, but on a very basic level,it is a dream world we live in.

I realize that is a hard-sell.

Just try to convince someone that they are merely actors in your dream world, and that they exist because you observe them.Likewise if they try to sell the same idea to you.

And therein lies the enigma-the mystery-the illusion of consciousness.

As for me, the classical world interpretation is good enough for practical purposes.

[quote]Everything we know about reality is based on our awareness of it, obviously.Nothing is totally real till we observe it, so in that sense, everything is in that gray twilight between dream and reality until we are conscious of it.[/quote]

Dangerous to trust your eyes only - stage magicians, evangelists and politicians have been fooling people at point blank from pre-history right up to the current day.

It is better to do the experiment yourself, then confirm that it tallies with what others have got in the past. Otherwise you can easily end up spending your life trusting YouTube videos of people burning hydrogen ash (water) as fuel, and getting free electric out of coils of wire.

The whole Cat thing was a paradox, as others have pointed out, it was set up as a "stupid example" of how QM *must* be wrong. Yet after a few decades of continuously improved experiments and subtle testing, it now seems that it is, in fact, both totally correct and completely ludicrous.

As for the tree falling, there is only noise if there is something there to perceive it as sound. Otherwise it is just another set of semi-random fluctuations in air pressure.

We can be aware of many things without seeing them.Why restrict the definition to sight only? I said "aware of" not "Seeing is believing".

Was Helen Keller aware of the universe around her? It certainly must have been a different perception that ours.

If she were in the room when the box was opened, would it affect the status of the cat, or would she have to sense it's pulse(or lack thereof) for the probability wave to collapse?

Open your mind to new avenues and do not become mired in the path well trodden, although it is much easier than blazing a new path.

Great roads have been paved following the trail of a fawn lost in the forest.

Later, Bambi.

If there is difficulty in understanding something, perhaps there is a too rigid adherence to the language used to describe it, or there is a failure in the language. Regarding the Cat, I would try feeding it some tripe, if it eats it it's alive, if it doesn't it's dead.

HTRN, let's take Schrodinger's experiment one step further: place the original experiment inside a larger box in which an observer is also placed. (I'll volunteer for the job provided I get free pizza and beer for my efforts afterward)

With the outer box sealed, after an agreed-upon interval I open Schrodinger's box and observe Boots as being either alive or dead. At an agreed-upon interval after that, you open the outer box and you see me petting a live, purring cat or see a closed Schrodinger box and me sitting there mourning Boots' demise)

There is an observer - me - who actually knows Boots' fate before you do, but you're The Observer in this experiment and I'm merely part of the von Neumann Chain which informs you of the fact. I am quite literally part of the QM system (as are you, but it is clearer this way).

Before you open the outer box, is Boots dead, alive or in a superposition of states? Does it matter that I know and you don't? At what point in the von Neumann Chain, then, does Boots' fate become indeterminate? Is not each link in the chain, in effect, an observer in its own right?

-e

The cat is EITHER dead or alive, not both.No matter how many boxes,or Russian dolls are nested within each other.

The state of the cat determines what is observed, not the other way around.The state of the cat is totally independent of the observer.If reality were dependent on an observer to collapse it from an infinite set of possibilities, then, as I originally stated, what consciousnesses observed the first event, the expansion of the universe from the singularity (according to the current theory)?

Did the universe exist before there was an observer? If yes, then reality does not require an observer, it just IS.

If no, then our universe is a construct of our own making.

An understanding of the universe is not required for me to enjoy it, however.

I do not understand women, but I totally enjoy them.

The real question is: does the Universe exist before coffee? (not Coherence Lite. It's worse than decaf)

Nice questions-thoughts-arguments... I could extend your thoughts by telling these:

The "official" interpretation of Quantum physics (Copenhagen) states that there is the need of an observation by a "consciouness" in order the "superposition" to be collapsed. It implies that such a "consciousness" must be a "human's consciouness". But this is not necessary. There is no need for a "high level consciouness". Even a "low level consciouness" could, also, be able to distinguish between an "alive cat" and a "dead cat". For example a dog could do that... or a frog... or a fish... How much "low" such a "consciouness" should be in order to consolidate a reality? E.g. is a worm capable to do that?

My personal opinion is that this "official" approach is wrong... There is no need for the world to be observed by a human being (or an inteligent animal) in order to become real. It was real before any living creature ever existed (otherwise in which way the living creatures were created?) And it is real... and it will be real... even after any living creature will be vanished...

For some religious people -who try to find a scientific argument in order to support the existence of God- these statements by Quantum physics are really nice: 1) There is a need for a "consciouness" for the world to be real. 2) The world -obviously- were real before the existence of any living creature. Hence, another kind of "consciouness" should be present. And this "consciouness" should be the God himself. The world was real from the begining of its existence, as the God (who created it) was, already, present and could "observe" it... (Very convenient indeed...)

I think that the "key" for the superposition-breakdown is not the "consciouness", but the concept of "interaction": Everything that interacts with something else should be real... The problem is that -as everything interacts with everything else all the time- everything should be always real... So, we shouldn't be able to observe (e.g.) the "interference pattern" image on the 2-hole experiment. I.e. how "strong" the interaction should be (e.g.) for an electron in order to be real?...

Exactly! There is no necessity for a conscious being to alter reality. It's all about interactions. It is of course via interactions that a conscious being (like a human) forces some quantum states - who happened to be in superposition - to collapse, but altering the quantum states is certainly not only human privilege.

Now, inside the box, all gazillions of particles and photons interact all the time, "creating" (i.e. solidifying) the reality in any fraction of time. The question is: Can the quantum condition (e.g the status of a decaying atom) which will decide the fate of the cat be under superposition for long in such a macroscopic system? Mind that the atom (or whatever) will have to interact with the rest of the matter in the box, for the mere reason to eventually trigger the demise of the cat, so it can hardly be considered as an isolated quantum entity happily minding its own business.

While we know that half of the atoms in a piece of radioactive material will radiate over it's "half-life", we do not know which ones. The one that will trigger the cat's death may not do so over the period of the test. I don't think that interaction with other particles is a trigger for an atom to radiate.

I think that the superposition collapses anytime that the particle is forced to identify itself, e.g. as it approaches a polarized lens, it must pick an axis of spin: in the one slit/two slit experiment, the superposition continues as the light can go through either slit but collapses when only one slit is open. the detectors record this whether we are looking or not.

Yes, spontaneous radioactive decay does not depend on interactions with anything else.

Sorry!

Recent research has found a deviation from random in the decay of particles.The deviation is centered around solar flares.This of course, means the deviation started BEFORE the flares were observed.

There are also indications that a global consciousness can cause an effect in the same way, but to a lesser degree.Such as prior to,during, and after 9-11,and other catastrophic events.This is from data analyzed from sources around the globe and complied to eliminate local variations.

This has a lot of people scratching their heads.This information is now being analyzed to perhaps predict solar flare events in advance.

Links? :)

As per your request, the solar link is below.

Refer to "Through the wormhole " TV series for the reference to "global consciousness" influencing radioactive decay.

http://news.stanford.edu/news/2010/august/sun-082310.html

I saw nothing about consciousness in that article. ???

The link referenced the solar aspect, and the collective consciousness is referenced in the tv series: "Through the wormhole", which also addresses the solar effect as well.

I will try to find the episode# for you if you cannot find it.

...I don't think that interaction with other particles is a trigger for an atom to radiate...

Of course not! I claim that at some point the atom will radiate and if this is made to cause the fate of cat, then cat will know it, even for the fraction of time before it gets killed. The atom will have to have interacted with other matter in order to be able to kill the cat, and therefore "reveal" to the world (and make this revelation quite macroscopic!) what it's status actually is. As soon as we have a collapse of its status (and therefore the cat's status), I can't see where is the superposition of the atom, let alone the whole cat, whether we peep inside the box or not.

On the other hand, if the atom has NOT yet radiated and has NOT yet interacted with the rest of the matter (either actively by killing the cat, or passively by being hit by a photon per instance), then it is surely in superposition, but it is an isolated entity that has not "authority" to tell what the rest of the system's status should be.

My point is that the fact that we don't know what happened with the atom until we peep inside the box, is not the same as to claim that the whole cat is in superposition. If this were true, we would then have to deal with another question: Did the opening of the peeping window affect the atom somehow and caused it to collapse to a certain state? If the opening of the window (and the permission of some photons to arrive to our eyes) has an effect on the atom, then we have to admit that infinite other causes inside the box would have caused the superimposed atom to collapse already.

Think it another way: Certainly every particle in every cat, whether participating in a weird experiment or not, will be in (and out of) superposition constantly for it's own reasons. Can we say therefore that cats are in superposition? If we agree to this, i.e. we break the distinction between quantum and macroscopic reality, then we have to admit that there is no "robust" reality whatsoever! We can only talk about "average" reality of many many quantum phenomena. Well, I'm afraid this gets too philosophical for me.

The Copenhagen Interpretation (one of many and not 'official' in any capacity) does not introduce the term 'real' nor does it imply that a QM system's final state is somehow a measure of reality. This is your term and without further clarification as to what 'real' means to you, the term serves only to cloud an otherwise well-defined problem as already stated by HTRN.

Just sayin'

-e

In a way, you are right. I used the word "real" not as a strictly "scientific term" but as a kind of "philosophic concept". By "real" I mean everything that is well defined by obervations or measurements. Of course, you could say that a "superposition state" is, also, well defined as probabilities (via Schroediger's equation)... and, anyway, the interference image in the 2-slit experiment is, also, very real (as real as the image in the 1-slit experiment is). So, yes, you could say that the "superposition state" is a reality too. Another kind of reality though, as it is not perceptible by the limited human inteligence. The Copenhagen Interpretation may not introduce the term "real"... but I felt free to use it for the sake of our discussion... (Often QM is hidden behind maths and general terms in order to avoid to give a simpler and clearer picture to the people... and, probably, this is right... as QM is still far away from the discovery of the deepest meaning and explanation of all these...)

BTW, the Copenhagen Interpretation may not be the "official" one but it is accepted by the majority of physists. After all, all the alternative interpretations (in my humble opinion) are not better than that.....

Thank you for your reply. G.K., I still tend to shy away from the term 'real' here because the probabilities themselves are no less real than the outcome itself! After we take the measurement, what we have is not something whose reality was ever in question, but the knowledge of what that reality is. Its description. We have information about state that we did not have before. Definite-ness. Whilst in the air, the state of Quantum Coin is unknown, but upon landing in our hand it is either heads or tails. The reality of the coin itself was never in question. What has changed is what we know about it.

-e

Hi E. You said: "... I still tend to shy away from the term 'real' here because the probabilities themselves are no less real than the outcome itself!..." I meant exactly that when I wrote: "... Of course, you could say that a "superposition state" is, also, well defined as probabilities (via Schroediger's equation)... and, anyway, the interference image in the 2-slit experiment is, also, very real..." So, it's obvious that a super-position state is a reality too...

I think that sometimes we are playing with words. After all, when Everet was talking about "parallel Worlds" or "parallel realities" (produced after the observation of a QM phenomenon) nobody blamed him for that (everybody understood what he was trying to say).

Of course, a particle which is in a super-position state, is 100% real and the probabilities of being in one state or another (when observed) is 100% real. This is the "reality" before the observation. But, after the observation we have "new realities". E.g. before the observation the photon behaves like it has passed through the two slits simultaneously. And this is a reality. But after the observation, we find out that the photon has passed through either slit#1 (reality#1) or slit#2 (reality#2). We could say that a new reality has been produced after the observation.

So, don't shoot me for that.....

OK, let me try to clarify my own logic (if possible).

I accept that the interference pattern exists in the 2 hole experiment, and that it disappears when "observed or measured". So how does one measure it?

By detecting the electromagnetic field of the photon? (which will affect the field, and the photon). By direct observation of the photon itself(this also interferes with the photon and the EM field).

I can name several explanations for this:

1: Interference(observation of any sort) changes the results of the experiment.

2. The photon is a particle and a wave simultaneously

3. The photon "knows" when you are looking at it and likes to mess with your head.

4. The photon makes multiple trips thru the holes at the same instant (or so fast we cannot detect the difference).

Take your pick.

Ok, consider a thought experiment of mine:

A plate with 2 slots in it.

A shotgun loaded with steel pellets.

The area between the slots is magnetized, on the back side only.

Fire the shotgun at the center of the divider, and as the shot pass thru, some are diverted from each slot toward the opposite side ,but they are not stopped by the magnet.The steel shot are analogous to the energy packet of a photon.

The photon is not a single particle, it is a "packet" of energy If you put the steel shot in a bag(A packet) before firing, the shot would be released from the bag upon impact.

The slot breaks up the energy packet of photons just as well.

When we attempt to observe what is happening, we neutralize the "magnet" by our observation, and the interference pattern ceases.

A photon is accompanied by an electro- magnetic field, and any attempt to measure it causes the field to become de-synchronized with the packet.

When synch is lost, the wave effect is lost.

IMHO

Just a wild thought:

What would happen if you put a different colored lens on each slot?This would reveal the separate origins of each wave,would it not? Perhaps Red and Green, then the interference pattern would be yellow where they interfere.

Or would this constitute interference?

Only if the police were involved.

Are you speaking of 'filtering' a single photon here? More than one? Ones of different wavelengths all mixing together?

Now your mixing how our eyes perceives the color of light with the frequency of a photon. This will quickly lead to more confusion.

How about firing electrons one-at-a-time through an aperture? They're much more cooperative in terms of doling them out one-by-one and keeping them all at about the same energy <==> wavelength. Very handy for doing slit/aperture experiments. And they have a measurable mass and act much more like particles than those ethereal photons.

Now, shoot enough of these buggers one-by-one through a tiny aperture and you eventually get an Airy Disk. None of this two-slit interference business, yet they still create an interference pattern. "But if they're arriving one at a time," (at the aperture in a straight line no less) you may ask, "what is interfering with what?"

Exactly.

-e

Just to reiterate your point, it gets spookier when you do the two slits, Young's experiment. The sum of many single electron trajectories interfere with themselves to make the dual slit pattern you expect of a wave going through both slits at the same time.

no dissenting

http://icanhascheezburger.com/2009/06/17/funny-pictures-nom-ptui/

>^.^< maw maw

Schrodinger's Watermelon? Who did you have to kill for that lol!

You guys just killed my inner buddhist.......thanks a lot

I don't think anybody thinks the cat has superposition, but sub-atomic particles may. The quantum computer that you keep pointing out has 3 states.

QM does not place an upper limit (nor any limit for that matter) on the size at which an object is no longer represented by the Schrodinger wave equation or by an ensemble thereof. That we are somehow Classical observers of a Quantum universe is as arbitrary as it is false. There is no limit on the size at which an object, be it a photon or a cat - or a human - cannot exist in a superposition of states. -e

You are right. Wikipedia gives several interpretations and some links. This one is described in the link and the article. They said they put the "the superconducting circuit into a superposition of two states, one with a current and the other one without.", but didn't explain how. I find that very irritating.

Well, that's the point isn't it? Seeing this apparent problem?

Being a thought experiment, this so called problem is easily resolved:
There is no cat.

Now put "self" in the box...

Ok, I'm in the box.

It is a case of:

I think,therefor I exist.

OR

I exist, therefor I think.

Doesn't work if I start with the premise that I don't exist.

Hence, I exist.

To exist doesn't necessarily mean that something or everyone thinks...anyway, am reproducing a similar problem/analogy for your perusal ie

\\Consider a collection of bombs, some of which are duds. Suppose these bombs carry a certain perfect property: usable bombs have a photon-triggered sensor which will absorb a photon and detonate. Dud bombs have a malfunctioning sensor which will not interfere with any photons.^[4] The problem is how to separate at least some of the usable bombs from the duds. A bomb sorter could accumulate dud bombs by attempting to detonate each one. Unfortunately, this naive process destroys all the usable bombs.//-wiki

https://en.wikipedia.org/wiki/Elitzur%E2%80%93Vaidman_bomb-tester

Is it permitted to disconnect the detonators, send the signals while listening to the triggers. If they hear a trigger click they reconnect the detonator of this good bomb.

I'm not sure of the relevance of this.

Live bombs and duds are like the same things 'existing' together at the same time .. yet separating them in two places does pose difficulty as discussed in the provided link.

I think matter cannot be made to exist in two places (alibi??) simultaneously unless matter is made to change form and distributed. I am not sure.

The problem with existing is that you are out of the 'small box' but still in the 'big box'

Problem with not existing being, people keep making the boxes for them!

'Not all thought experiments, or apparent paradoxes, or other conundrums are designed to be resolved. Many are created to offer an opportunity to reveal the nature of this need to resolve everything. See: Zen Koans.'

Metaphysics and Quantum Physics

"If an electron can be at two places at one time, why can't we?" This is an exciting proposition, and it reminds me of a story my Pakcik told me about his experience in his younger days. ''

http://www.mindpowernews.com/TwoPlacesAtOnce.htm

----

''Einstein was the first to embrace quantum physics but later rejected it on the grounds that it made everything unpredictable - "God does not play dice with the universe," he famously stated.''

http://www.independent.co.uk/news/science/einstein-was-right-you-can-be-in-two-places-at-once-2162648.html

more....

http://www.newscientist.com/article/dn20712-how-to-be-in-two-places-at-the-same-time.html

"If an electron can be at two places at one time, why can't we?" This is an exciting proposition, and it reminds me of a story my Pakcik told me about his experience in his younger days. ''

The electron cannot be in two places at once, there is only a less than 100% probability of it being at each of many places, a probability wave. When you force it to identify itself, the wave collapses and all of the probabilities merge to one place; that probability becomes 100% at that one place.

I will look into it. But Discovery must have stated this after some research or study:

"If an electron can be at two places at one time, why can't we?"

Here the word ''IF'' points to something crucial!!

Hi HiTekRedNek;

In my less than perfect world, Schoedinger retired from the Philosophy Department here a Boise State University around three years ago and he nolonger has a cat since his wife passed away!

However these conjectures you suggest in your diatribe are somewhat parallel to the twin photon theory which has been widely discussed over the past 15 years, and some proponents of one view point of it hold that if a tree falls in the woods and there is no one there to observe it or to hear it, then did a tree really fall? Was there even a tree? Some eclectics believe that reality creates itself for each and every viewer and enfolds as it is created in the eyes of those viewers. Extremely scientific tests have been conducted using twin photons in a cesium gas chamber at USA universities that analyzed the coincidence rates of comparision between them and it was found that whatever was done to one interacted upon the other more than by a random measurment. These tests verify their connection, maybe not often enough that in their given circumstances the unique properties they exibit could someday be used to establishing a new communications mode which could possibly easily be much faster than the speed of light. I hope I haven't drifted you off topic here but you did go far afield from where you started as you progressed in your scenario, so I thought this might be fun to explore as long as we were far distant from where it all began! Godspeed Now!

Professor Lowell A Morton

Administrator of Virtual Universities

"... the twin photon theory which has been widely discussed over the past 15 years, ..."

You're kidding, right?