Cats Alive! - A Quantum Puzzle

If we put a female cat during the period of fertilization, beside the box, then the cat inside the box will react, if it is alive

I don't know why you need a box and all the other stuff for, the cat, or any other living thing, when not being observed, can be said to exist in this undefined state....It doesn't mean it is both alive and dead at the same time, it means it has the possibility to be one or the other...and we can add further the dimension of time.... the cat, being observed at a great distance, is being observed in the past, at the present time....The only thing that can be said for sure is that the default state of the cat is death, and that it is sometimes seen alive, albeit a rare occurrence.....er, aaa, what was the question again?...zzzzzz

The isolated observer has stated that she KNOWS the state of the cat. To make a statement with that certainty the cat must be dead, the only non reversible state.

The only way her statement could be considered as fact, is to eliminate the possibility of human error....

I suppose I ass u me d that the observer would be ultimately capable and trustworthy.

Otherwise why be allowed to be the observer. Multiple human error ? lol.

Well we do have multiple precedent....

I am amused each time these cat-in-the-box questions come up. Long before I took any interest in Relativity and Quantum mechanics, I used to wonder about the result of my exams, by a certain date I knew that the result should be in the mail, but that it wasn't real until I saw it. I even conjectured that it could change while on the way but I would not know it.

Another example: We have sent a number of space probes to land on Mars, some of which have crashed. There are no observers within light minutes of the event. Do they really exist in a superposition of crashed/OK before any observers on earth can find out?

Hi Theophilus. About your questions:

1. Whom is correct and why?

The observer inside the box is correct. Just one observation of a quantic state is enough (and necesary) for the superposition (quantic wavefunction) to be collapsed. The observation has been done by the internal observer, so the superposition is already collapsed.

2. For her the wavefunction has collapsed, but for him it has not, so has an observation - a measurement, in the QM sense - really occurred or not?

A measurement has already occured (see 1.)

3. At what point did the wavefunction collapse, or has it?

The wavefunction collapsed right at the moment of observation of the internal observer.

4. If they fail to publish their results, but instead keep them a secret forever, does Schrodinger's Cat still exist in a superposition of states?

It doesn't matter. In any case the superposition is already collapsed.

Just to be accurate: What I've mentioned is the official Copenhagen interpretation. However, several philosophical questions arise by this approach. First of all, it gives to the "observation by a human being" a rather metaphysical, superior quality. Why such an observation should be so special? Someone could say that there is no need for an "observation by a human being" in order the superposition to be collapsed. Just the observation by an "inteligent being" is enough. So, the question is how much "inteligence" is needed for that? E.g. I'm sure that a gorila is clever enough for that. But even an animal of a much lower inteligence can distinguish a "living cat" from a "dead cat". So, can a mouse cause the collapse of the superposition? Or a worm? Or a bacterium?

My opinion is that no "observation by a human being" is needed for that. In fact no observation of any kind is needed at all. I suspect that just the interaction of a quantic system with another system is enough for this collapse. (Afterall, our brain is nothing more than a complicated, smart system.) I'm not sure about how much intensive this interaction (between these systems) should be, in order this collapse to be occured. (Probably, even the interaction between a few particles is enough for that.) In any case -if this approach is correct- then, in the Schrodiger's experiment, the superposition is collaped at the exact moment that the Geiger counter measures the disintegration of the radioactive nucleus (and not at the moment of the observation).

the superposition is collaped at the exact moment that the Geiger counter measures the disintegration of the radioactive nucleus (and not at the moment of the observation).

Good point!

I always was of the opinion that as soon as a system (even one single nucleus) interacts with another system, then superpositions will collapse (as well as created at the same rate): The "observer" need not be intelligent. After all, intelligence is a macroscopic feature that implies emergent complexity, for which a tiny stupid nucleus know nothing about. (Otherwise, imagine the dilemma of the nucleus to collapse its state, wondering whether its observer is blonde or not... ) Take also the case an automatic camera takes a shot of the cat inside the box. Does the cat's fate is decided the very moment the shutter opens, or when an "intelligent" observer views the photo?

Observation for me (although arrogant it may seem for an non expert), means interaction with photons, or any other particle for that matter. It is via those means that a state can be known to any observer, intelligent or not. And as soon as we have photons traveling around (the box's temperature is over the absolute zero, right? Otherwise, we know for sure what the cat's state is!) and bumping all over the place inside the box, then quantum superpositions get collapsed (and created) every single jiffy.

I wonder how the Copenhagen interpretation deals with this approach.

A gorilla or mouse or dog or eventually even a human would know the state of the cat once it had died without opening the box ( by the smell, ass-u-ming the box was not otherwise sealed, which would kill the cat anyhow ). just joking there.

but seriously,

What about the observer in question ? she said she KNEW the state of the cat. Since she did not continue to observe, the state must have been DEAD since if the cat was still alive, once the observation took place and the box closed again, it would be as if the experiment had only just started.

To Firmly say " I KNOW " the state of the cat Positively identifies the state since that is the only state which could be positively known without further or continuing observation.

is that logic wrong ? why ?

I think now they talk about de-coherence rather than observation by a human or other observer. My understanding is that if a system (say an atom) remains isolated from the external universe, the coherence is maintained. A lot of the work on quantum computers involves extending the coherence time of a quantum system.