Schrodinger's Cat. WTF.

[TheLonelyPhoenix]

And the fact that the probability is 50% doesn't play a role?

Actually, yes, that's exactly right. All possible states are true at once until the system is "observed", forcing the system to take on only one of its possible states.

 

[KDOG]

Wow this is interesting. I've been thinking about this stuff all night. As of right now, I believe Schrodingers' belief that the cat is in only one state - whether we observe it or not. I base this on the concept of reality as in OUR reality. Since the cat, the box the "diabolical" mechanism were all formed in our reality, all of those would behave according the physical laws of THIS reality regardless of a completely sealed barrier (the box). So therefore the cat is EITHER dead or alive inside the box, not both, and whether it is observed or not makes no difference.


I can't believe I just came up with that. My brain is goo.....

 

[CrackRabbit]

Easy, Schrodinger's cat is a zombie. If you open the box to observe it you start the zombie apocalypse.

 

[Zorkorist]

Fucking Zombies!

-John

 

[Cerpin Taxt]

Wow this is interesting. I've been thinking about this stuff all night. As of right now, I believe Schrodingers' belief that the cat is in only one state - whether we observe it or not. I base this on the concept of reality as in OUR reality. Since the cat, the box the "diabolical" mechanism were all formed in our reality, all of those would behave according the physical laws of THIS reality regardless of a completely sealed barrier (the box). So therefore the cat is EITHER dead or alive inside the box, not both, and whether it is observed or not makes no difference.

But you see, that isn't the way the physical laws of our reality actually work. Rather, it is the way our sensory perception works. The thought experiment is useful to illustrate the counter intuitive nature of reality at the quantum level.

As another example, we can consider an electron orbiting an atom's nucleus. The electron is sort of "everywhere at once" but not "entirely in any one place." This is the natural state of the electron. In order to observe it, we must interact with it, and in order to interact with it, we must affect it's position and velocity, taking it OUT of it's natural state and "pinning it down" to a certain place and/or time.

Schrodinger's thought experiment ties the state of the cat to the state of the quantum particle, so if it is true that the particle is "everywhere at once" but "no place in particular," then the same must be true for the cat. Thus, the cat is "sort of dead" and "sort of alive" until we interact with it in order to observe it.

 

[TastesLikeChicken]

No. Quantum theory says the cat is simultaneously both dead and alive until it is observed.

Quantum theory really doesn't say that. Quantum theory only applies to quantum systems, not macro systems. Shroedinger's Cat is merely an analogy that describes the strangeness of quantum behavior on a macro level.

I subscribe to something akin to the many worlds scenario but don't really believe in waveform function collapse, or decoherence. imo, waveforms don't really collapse. It's just that, by observation, our reality subscribes to one potential result of the overall possibilities and once we do that all other results move beyond the capabilities of our perception. iow, quantum behavior only appears strange to us because of our inherent observational limitations.

 

[silverpig]

Quantum theory really doesn't say that. Quantum theory only applies to quantum systems, not macro systems. Shroedinger's Cat is merely an analogy that describes the strangeness of quantum behavior on a macro level.

I subscribe to something akin to the many worlds scenario but don't really believe in waveform function collapse, or decoherence. imo, waveforms don't really collapse. It's just that, by observation, our reality subscribes to one potential result of the overall possibilities and once we do that all other results move beyond the capabilities of our perception. iow, quantum behavior only appears strange to us because of our inherent observational limitations.

Quantum theory works perfectly well for macro systems.

 

[TastesLikeChicken]

Quantum theory works perfectly well for macro systems.

Can you be a bit more specific?

I'm asking because in some cases that is true and in others, imo, it is not.

 

[Analog]

Can you be a bit more specific?

I'm asking because in some cases that is true and in others, imo, it is not.

See Silverpig's ball in box example above.

 

[Fox5]

Schroedinger's cat could be dead or alive, depending on the conditions of the measurement.

My best explanation (possibly wrong):
Quantum mechanics is a statistical interpretation of reality. A particle has non-zero (but not equally likely) possibilities of being in any multiple states until it is observed to be otherwise. Likewise, there is some probability that the cat is dead, some probability that it is alive, and the conditions of when/how the measurement is taken will determine which is seen, with some amount of uncertainty associated with that measurement.

 

[Ninjahedge]

It is simple.

If you cannot prove something by any external evidence, then it can be anything. Not just the cat, but figure a black box.

You get a box the size of a college cube fridge on your living room floor where you and 7 other recently deceased people all of a sudden appear for no reas... wait a sec, that is an Anime...



Back to the original though. You get a box on the floor. Certain parameters such as size, construction of the box and the like can eliminate some contents such as fluids, burning coals or Rosanne Barr.

But if this box could have come from ANYONE (say Bill Gates starts playing pranks on Rich Jackass 3D II), then just about anything from chicken feathers to gold bars could be in there.

Would you keep the money or go for what's in the box?


The premise is, if you do not know, there is a chance (not necessarily equal) that it could be just about anything.

In the cat example, all you would have to do is wait a few months and you have now put another variable into the equasion that you know about. Feline halflife. Your cat will be dead if you leave that box for a month on the floor (ok, maybe 3 months). But that only comes from additional knowledge and conditions imposed on the situation.

It isn't the perfect analogy for Modern Physics, but hopefully it lets people understand the concept of not knowing what you do not know...... (so blindingly simple most people just don't get it).

 

[Arcadio]

Quantum theory works perfectly well for macro systems.

This. Whether you like it or not, quantum theory works for objects big and small.

 

[crashtestdummy]

Can you be a bit more specific?

I'm asking because in some cases that is true and in others, imo, it is not.

What happens in larger systems is that the "error" imposed on classical measurements (location, velocity, etc.) becomes negligibly small. For example, electrons often cross energy barriers that would be classically impossible. It's called quantum tunneling and is an effect widely used in electronics. Similarly, I could continually walk into a brick wall. There is a finite chance that I could show up on the other side and continue walking, but I'd have to wait 180,000 times the age of the universe for such an event to be likely because the barriers and distances are much larger than the spread of my wavefunction.

 

[crashtestdummy]

It is simple.

If you cannot prove something by any external evidence, then it can be anything. Not just the cat, but figure a black box.

You get a box the size of a college cube fridge on your living room floor where you and 7 other recently deceased people all of a sudden appear for no reas... wait a sec, that is an Anime...



Back to the original though. You get a box on the floor. Certain parameters such as size, construction of the box and the like can eliminate some contents such as fluids, burning coals or Rosanne Barr.

But if this box could have come from ANYONE (say Bill Gates starts playing pranks on Rich Jackass 3D II), then just about anything from chicken feathers to gold bars could be in there.

Would you keep the money or go for what's in the box?


The premise is, if you do not know, there is a chance (not necessarily equal) that it could be just about anything.

In the cat example, all you would have to do is wait a few months and you have now put another variable into the equasion that you know about. Feline halflife. Your cat will be dead if you leave that box for a month on the floor (ok, maybe 3 months). But that only comes from additional knowledge and conditions imposed on the situation.

It isn't the perfect analogy for Modern Physics, but hopefully it lets people understand the concept of not knowing what you do not know...... (so blindingly simple most people just don't get it).

I feel like the mistake of this kind of analogy is that it gives the impression that there are "hidden variables" that are fixed and we are just not at the moment able to observe. This is not the case. It is not that the cat is either alive or dead in the box, but we just don't know it yet. It is that the cat's life is tied to a probability function that remains indefinite as to life and death until it is collapsed by an observation.

 

[KDOG]

I don't buy the double slit experiment either. I mean I believe that what they say happen happened, but I don't agree with the interpretation. How the heck would the electron "know" if it was being observed? It wouldn't. Its silly. Obviously whatever equipment they added to observe the electrons changed the environment and caused the electron to behave differently.

 

[Ninjahedge]

CTD- Yep.

The basic rule of science: KeepItSimpleStupid.

As for "Unknown Variables" those are just curve fitting fudge factors. You have them in just about anything.

When they are conservative they are called "factors of safety" and applied to things like soil behavior...

 

[silverpig]

Can you be a bit more specific?

I'm asking because in some cases that is true and in others, imo, it is not.

It's mostly because almost all hamiltonians have a factor of h(bar)/2m in front of them.

hbar = 1.05457148 × 10^-34 m2 kg / s

m is the mass of the object in question. The reason why all these funky quantum things happen when you look at small things like electrons is because of the electron mass:

electron mass = 9.10938188 × 10^-31 kilograms

Compare to a person:

person mass = 90 kg

Now let's look at what h(bar)/2m is in each case.


h(bar)/2m [electron] = 5.78838109 × 10^-5 m2 / s
h(bar)/2m [person] = 5.85873042 × 10^-37 m2 / s


As you can see, there is a factor of 10^32 difference between the two systems. Right off the bat, if you consider quantum tunnelling, before you've even done any kind of hard calculation, you're 10^32 times less likely to tunnel as a person than as an electron. Add to that the fact that you generally consider much larger barriers in the macro scale (walls etc), and you'll get another factor of about that size.

This isn't of course a full calculation, but I've done a simple "calculate the probability that an electron will tunnel through this barrier" problem, and then repeated it with a truck tunnelling through a speedbump. The equations were essentially the same, just the masses and distances were different. I think there was a factor of 10^100 difference between the answers.

 

[silverpig]

I don't buy the double slit experiment either. I mean I believe that what they say happen happened, but I don't agree with the interpretation. How the heck would the electron "know" if it was being observed? It wouldn't. Its silly. Obviously whatever equipment they added to observe the electrons changed the environment and caused the electron to behave differently.

Yes of course. That's the point of the experiment. Double-slit is one of the best done quantum experiments.

 

[KDOG]

Thats not what I mean. What the experiment is saying is that the electron had some sort of "sentient awareness" of being watched and just "decided" on its own to do something different. I don't buy that. What I'm saying is that whatever equipment was added to do the observing had a direct physical effect on the environment and the electron itself. I'm still working this in my feeble brain.

 

[silverpig]

Thats not what I mean. What the experiment is saying is that the electron had some sort of "sentient awareness" of being watched and just "decided" on its own to do something different. I don't buy that. What I'm saying is that whatever equipment was added to do the observing had a direct physical effect on the environment and the electron itself. I'm still working this in my feeble brain.

Again, this is the point of the experiment.

When you put some piece of equipment there that doesn't extract any information out of the environment, the electron can interact with it without being changed. The electron goes through both slits at once.

When you extract information from the electron, you change it enough that it goes through one slit or the other. The electron doesn't decide anything, it just is.

 

[Gibsons]

It does during the measurement yes, but the system will evolve again as soon as you remove the measuring influence.

Think of it this way: You've got a rubber ball in a sealed dark box and it's bouncing around like crazy. You don't know where the ball is in the box, so you say it's "everywhere" with "equal probability". You have a camera which is hooked up to a glass window on the side of the box and a flash. You take a picture. The flash lights up the ball and the camera takes its picture. You can see exactly where the ball is at that time (the wavefunction collapses from "it's everywhere" to "it's right there", but after the measurement, the system continues to evolve.

The system doesn't evolve, the FSM intelligently bounces it from one side to the other, in accordance with his noodly will.

 

[crashtestdummy]

Thats not what I mean. What the experiment is saying is that the electron had some sort of "sentient awareness" of being watched and just "decided" on its own to do something different. I don't buy that. What I'm saying is that whatever equipment was added to do the observing had a direct physical effect on the environment and the electron itself. I'm still working this in my feeble brain.

It didn't decide anything. The photon was a wave with a multimodal probability distribution. Since an observation requires that the photon only be in one of those places, the wave function collapses under the observation down to a specific point, where all other information (including the above wave function) is destroyed.

Now, with that said, what constitutes and "event" and how a wave function can collapse like that is still a mystery, and is the one of the key missing pieces to the Copenhagen interpretation.

 

[SlitheryDee]

There's a cat named Schrodinger on a level in bioshock. It was dead; frozen solid to be specific.

I have no more to contribute.

 

[Ninjahedge]

Was it waving?

 

[Matthiasa]

What happens in larger systems is that the "error" imposed on classical measurements (location, velocity, etc.) becomes negligibly small. For example, electrons often cross energy barriers that would be classically impossible. It's called quantum tunneling and is an effect widely used in electronics. Similarly, I could continually walk into a brick wall. There is a finite chance that I could show up on the other side and continue walking, but I'd have to wait 180,000 times the age of the universe for such an event to be likely because the barriers and distances are much larger than the spread of my wavefunction.

I had that happen once.
Tossed something at a wall and it neither hit the ground, wall, ceiling, or myself.