Schrodinger's Cat

Just don't see why a cat in that condition needs to be put in a box.

We have a saying

a cat in a bag, (not in a box)

The oxygen will be consumed in the box, say e.g. initially 21%

This percentage decreases in time. The cat will fall asleep (sleepy- dead and become deader - where to stop?)

You will need to monitor the cat too to conclude what you are up to.

And opinions differ.

Don't let the cat out of the bag.

let the cat out of the bag - Idioms by The Free Dictionary

Or,

This cat is like a:

Pig in a poke - Wikipedia, the free encyclopedia

Thank you for the idiom, we say somewhere in Europe:

buy a cat in a bag, like buy bad, something you haven't seen and turns out to be a disappointment.

Jack's right. The oxygen monitor is now monitoring the cat, just as the Geiger counter is monitoring the uranium atom.the only way to keep the experiment valid is to not have the oxygen monitor directly observed. Also, who ever said the box was airtight?

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Of course, the way the experiment is described in most cases, there is no barrier between the cat and the uranium atom, so the atom HAS an observer, but since the observer is protected from observation, it is in the same state of quantum flux as everything else within the box.

However, cats tend to be cleverer than most people give them credit for. Perhaps subject A-113 (Known in the pet shop as 'Tabby') has an idea what the experiment is about, and what the experiment will mean for its continued existence as a 'live cat.'

Keep watching.

Keep staring.

Don't. Blink.

The original interpretation of quantum phenomena, the Copenhagen interpretation championed by Neils Bohr, was that an indeterminate event like the decay of a radioactive atom became determined (collapse of the wave function) when it was observed. This begs the question of what the meaning of observed is, whether it requires a human, a cat, a video camera, etc. Irwin Shrodinger put forth the example of the cat in the box to illustrate the problem with this interpretation. (A good question is did the wave function ever collapse before there was life on earth?)

https://en.wikipedia.org/wiki/Wave_function_collapse

The more modern interpretation is that a quantum system is isolated from the rest of the universe, and the "wave function collapses" when it interacts with the outside world, a process termed "Quantum Decoherence". This is the interpretation guiding the design of quantum computers.

https://en.wikipedia.org/wiki/Quantum_decoherence

Direct or indirect observation is actually full blown information from the "inside" hence not the original scenario. Anyway, the scope of that paradoxology was to challenge quantum fundamentals when applied to everyday objects, not to provide a new theory, so no glory here. S.M.

You are still monitoring the cat.

What's the difference between your proposed O2 monitor than a camera catching reflected photons, or a microphone, or a vibration sensor, or inertial sensor that detects the slightest movement of the box or the heartbeat of the cat, or thermal analysis?

The idea of the box in the thought experiment is to create an isolated closed system.

You are right, but let me extend it a bit, expressing at the same time an inquiry I always had:

What's the difference between a photon going to a human eye, or a measuring device, or a photon that just bounces around the box? I mean, it is the photon itself that collapses the superposition, or the destination of it? From my understanding, the 2nd one is broadly accepted. One may argue that the photon itself is part of the super-positioned system, but this makes me wonder, why a measuring system or a conscious being should not be a part of this superposition also. At which level of emergent complexity we have the boundary between the quantum and the macro world?

I tend to believe that all are superimposed, and the conscience choses one arbitrary explanation of the reality in order to avoid going mad. Sounds like parallel universes theory, but I don't know. Any idea?

I don't think the observer must be conscious--only that it must react to, say, photons.

I don't think the observer must be conscious--only that it must react to, say, photons.

... but don't the box walls react to photons too? So again, does the state collapses when a photon reaches it's destination (eye, instrument, wall), or when it actually interacts with the superimposed system? Is the photon itself superimposed? If it was emitted thermally from the box wall, then the wall is also superimposed? And if the inside of the box is superimposed, the outside isn't? Where is the boundary between the two worlds?

I think that as long as there is no truly isolated system, then the thought experiment, cannot be anything more than just a thought experiment.

No, I think you are describing decoherence, where it reacts in an irreversible way thermodynamically, and not a complete wave function collapse.

It does define the quantum state the two objects are in and that becomes a subsequent starting point for the range of possibilities for both the photon and whatever it interacted with.

Personally, I'm going to go feed the damn thing and change the litter box.

I won't be visiting your place!

I think it is the interaction that you are interested in. I don't think the interaction actually collapses the wave function, but it simply defines or pins down the state of that photon and whatever it is interacting with at that time and local. From that point forward each follows the Schrödinger wave equation based on the state they were in when they interacted.

"One may argue that the photon itself is part of the super-positioned system..."

I think your argument is valid.

"...why a measuring system or a conscious being should not be a part of this superposition also. At which level of emergent complexity we have the boundary between the quantum and the macro world?"

Well, they are once the interaction takes place.

The whole thing is kind of fuzzy because we really don't understand the process of wave function collapse, decoherence, or defining where and how a wave function collapses (the measurement problem) yet. That's not surprising given we really don't understand much about quantum mechanics to begin with, but that doesn't mean it is not exciting.

"I mean, it is the photon itself that collapses the superposition, or the destination of it? From my understanding, the 2nd one is broadly accepted. One may argue that the photon itself is part of the super-positioned system, but this makes me wonder, why a measuring system or a conscious being should not be a part of this superposition also."

Yes, you can have that. You sit in another room and have a research assistant open the box. If he sees a live cat, he is to enter your room through the West door and tell you. If he sees a dead cat, he is to enter through the East door and tell you. Until the door is opened, you now have a single research assistant standing outside your office on opposite sides of the building at once, because he is entangled in the quantum superposition until you observe his entry.

Also, there's already a conciousness in superposition within the experiment, even in its basic form. Remember the cat? Mittens is an Observer as well.

There's some point where we stop talking about 'superposition' and start talking about 'probabilities,' but it's trying to find where the line is that's the tricky part. We say an atom is in superposition, but we say the research assistant's location is a probability. Perhaps the line between quantum and classical physics is itself a quantum entity, the more we know about its location, the less we know about its 'edge.' Or to put it another way, when we don't know where it is, we see it as a sharp line, but the closer we get to finding it, the 'fuzzier' it gets, and if we *DO* find its location, all we've found is the point where the probability of an event being Quantum or Classical are 50-50, with the boundary now a shallow slope from 'Always Quantum' to 'Always Classical.'

But all this is going way into theory of theory, and I've got too much to do today to burn through my morning caffeine on a potential endless recursion loop.

"you now have a single research assistant standing outside your office on opposite sides of the building at once"

No. That would not be the case.

From a quantum perspective, yes, that WOULD be the case.

Notice that I said nothing about any other observers, aside from 'you,' the research assistant, and the cat. For the purpose of the experiment there ARE no other observers.

So The Experimenter sitting in his office knows nothing about the state of the atom, the state of the cat, or the state of the research assistant until a door opens. From the Head Researcher's frame of reference, all three are in a 'state of flux.'

In the Real World, there are many, many Observers, and past a certain threshold, physics behaves according to the Classical⁽¹⁾ model, so observation is not required to know the results, but in the Schrodinger's Cat experiment, we are deliberately limiting access to observation, and reducing the variables, in order to 'force' the Classical Physics world to act as the Quantum Physics world. The effects within the experiment, much like Quantum Physics itself do not make immediate sense to anyone thinking only in the Classical model.

Notes:

1. Actually, Classical (Newtonian) Physics has been replaced by Relativistic (Einsteinian) Physics, but for day to day live on Earth, the variation between Newtonian and Einsteinian are so small that we can use the simpler formulas and get results 'close enough' to work with.⁽²⁾
2. And that's the real challenge to Quantum Physics. If it is to replace Relativistic Physics, it needs to encompass all of Relativity, just as Relativity encompassed all of Newtonian. So far it seems to only be describing a 'parallel world' sitting 'under' the world we know, with little interaction between the two.
   

To my knowledge QM describes the micro world and Relativity the macro.

The problem is really the definition of gravity, which the two approaches can not agree. Other than that it isn't a conflict.

Yes, but the two aren't REALLY 'separate worlds,' the macro is made up of the micro, and the micro 'lives' in the world of the macro.

The Schrodinger's Cat thought experiment is asking the question, "Where is the 'boundary' between macro and micro, and how sharp or fuzzy is that boundary?"

Although, now that I type this, I'm beginning to realize that the 'experiment' might have been more on an analogy, a way to explain superposition in ways that people could understand without knowing all the math. The cat is in superposition between 'alive' and 'dead' until the box is opened. Those are states that people can understand, where 'decayed' and 'not-decayed' might be confusing. We do not know the states of subatomic particles until we observe them, and some particles seen to be able to switch back and forth between states, or take on contradictory states at once, when not being observed. Think of the two-slit experiment, or that character from Mystery Men, Invisible Boy, a guy who could become invisible when nobody was looking at him⁽¹⁾. Quantum doesn't seem to make much sense to us from a macro standpoint, so we need comical, almost rediculous metaphors to describe it.

Notes:

1. Invisible Boy actually *DID* become invisible at one point in the movie. All the heroes looked away, and IB walked slowly through the motion-detector area to get to the controls. As 'non-observer' observers, we, the audience, got to watch him vanish on screen, his empty costume falling to the ground.⁽²⁾
2. And yes, someone commented about his wardrobe after he turned off the security grid and the heroes could turn around and look at him.
   

"but the two aren't REALLY 'separate worlds"

That is true, but the models used to describe them are, and that is the problem. Relativity does not describe what we observe on a sub atomic scale and consequently Field Theories were developed to bridge the gap, but gravity keeps getting in the way, so to speak and there isn't one set of mathematical equations that work across the board.

You are right that the cat thought experiment was just a way to describe the paradox.

"You are right that the cat thought experiment was just a way to describe the paradox."

So, as an analogy, any 'mid-level observer or instrument' between the atom and the Head Researcher would become 'entangled' in the quantum flux until the Head Researcher gets his report.

Oh, this is really becoming a twisted, tangled, mess, sort of like a wibbly-wobbly, timey-wimey ... ball. I think I'm just going to sit back and wait for my brain to stop spinning. Or perhaps I should just get some more coffee so I can think faster...

(Been a while since I did a 'coffee-addiction' joke, it felt due.)

Thoughts? Sure. It is unwise to stop taking prescription medication without involving a medical practitioner.

That is why the famous Schrödinger's Cat can be both dead and alive. Schrödinger's cat is a thought experiment in which a poor cat is put in a box with a flask of poison and a radioactive source. If an internal monitor detects radioactivity, the flask is shattered, releasing the poison that kills the cat. But as long as we don't check the monitor, we have to consider the cat both dead and alive.

http://www.science20.com/news_articles/how_we_discovered_an_impossible_material_it_conducts_electrity_and_doesnt-156497

Regards JD

Just put Del in the box, and he can tell us.

Medicines have a shelf life, Food has a shelf life. Just because the expiration date has been met does not necessarily mean the product has expired.

So it waits till late at night, unobserved or seen till the moment you need that sip. Surprize.... or is it?

Regardless of how much oxygen the cat has. The original experiment included a vial of deadly gas and a radioactive atom who's nucleus can collapse at an indeterminable time. That is what creates the superposition. Is that we won't know if that atom's nucleus collapsed until we open the box and observe if the cat is dead.

If the cat has an hour of oxygen but a second after you seal the box the nucleus collapses, the vial is smashed open and the gas is released killing the cat, you won't know the cat is dead until you open the box and observe the cat. So the superposition still exists for the entire time the cat went unobserved.

That's a beautiful story. I love a happy ending.

The thought of [potentially murderous] geeks being killed always brings a tear or two...

...unless, of course, the critter being sacrificed is kind of ugly or otherwise scary.

After the tragedy was discovered, Schrödinger called the local police who arrived to do a through investigation. One detective, preoccupied with the cat, ask professor Schrödinger, "Good sir can you tell me what happened to the cat? Did it survive?"

To which the good doctor replied, "How the hell should I know if its dead or alive, I can't see it!"

And now you know the rest of the story

"...the cat, well experienced at being the "subject" of university hospitality,..."

"Everyone in the room died, except for the cat."

So the cat came back,

the very next day.

The cat came back.

They thought he was a goner,

but the cat came back,

he just wouldn't stay away, away, away. Oh, oh, ohhh.

(Sorry, couldn't resist.)

1. Obtain box - any old box will do (provided there is an ample supply of duct tape, baling wire, and WD40.

2. Install cat in box- any old cat will do, but select the cat that seems the most annoying at the time.

3. Place box - careful placement is necessary to see if the wavefunction can be collapsed.

4. Get in Truck - most any truck will do

5. Make sure cat is not under the hood, resting on the radiator fan

6. Start truck - the usual way

7. Drive forward to see if box (wavefunction) collapses.

8. If the wave function collapses, you may assume the cat did not make it.

Did you ever try to put and keep a cat in a box: you will know that it is alive.

"After many years of ignoring the pitiful meows, it was finally determined that Schrödinger's cat was, in fact, dead."
Thanks to [Josh Kopel] on Hackaday, Caption CERN Contest wk 23

I contend that it is not the state of the cat that is in a state of superposition,rather it

is the knowledge of that state that is in superposition.

One cannot know until one observes.

If the known life span of the cat is 1 year,and you do not observe the cat's state for 100 years,you can be certain of the state of the cat without observing it at all.

You have not violated the isolated system,yet you know the state.

But you take twin cats from the same litter, the only difference is one is left-pawed, and the other right-pawed (hypothetically), place both of them in Shroedinger's boxes, it takes two boxes. Now remove one of the boxes to the opposite side of the solar system (or as far as you wish or are able), and one will want outside if the other is out, or inside if the other is in. They will need to fed at the same time, or strange causality at a great distance may take place.

See post #4 above, its about as simple as I can explain it.

Again, empirical knowledge ruins the premise of the experiment.

In your current example it is the knowledge of the cats natural lifespan. The same goes for how long the cat can survive without oxygen, water or food.

After a period of time you know the cat will almost certainly be dead and hence the state cannot either be alive or dead with an equal amount of certainty.

The experiment is not just about observation alone.

Try this. Replace the cat with a coin. Toss the coin in the box, observe the outcome and close the box. What state is the coin in, heads or tails? You are not observing it in the closed box but prior knowledge has ruined the experiment because you know it is almost certainly in the same state as you left it.

Leave the room the box is in. Someone else walks into the room and then later back out. What state is the coin in now? You cannot know because you don't know if the person moved the box changing the coins state.

Ask the person if they touched the box. They say no. Experiment is ruined again because you now know the coin is in the same state you observed when it went in (certainly not a 50/50 chance of either state).

Through all this you did not violate the isolation system and didn't observe the coin in the box, but prior knowledge before the experiment began ruined the premise of the experiment.

Does that help?