schrodingers cat?

Question

After the box is closed, the cat is said to be in a state of superposition of |dead> and |alive>. Now the person carrying out the experimnt peep into the box and find that the cat is alive. So, it is said that the act of looking causes the wavefunction of the cat to collapse and, in this case, it collapse to the |alive> state. When the box is closed again, the wave function of the cat starts to smear out and after a while one would say the cat is back to the superposition state of |dead> and |alive> again. Intuitively, this cycle can be repeated over and over again as long as the cat is still alive.

Now, if the person peep into the box and saw the cat dead. It is said that the act of looking caused the state of the cat to collapse to the |dead> state. But if the box is closed back, can one say that the cat is back to the state of |dead> and |alive>? If so, could it be possible that the next time someone peep into the box, the cat is back alive? If not, why is the there an asymmetry?

Answer 1

tThis problem might be easier to understand if you use polarized light instead of a cat. Polarized photons can be viewed as a superposition of 2 orthogonal states, which we can arbitrarily chose the vertical and horizontal as the states. If we pass a vertical polarized light through a 45° polarizing filter, we end up with a beam of photons that are in a superposition of being both vertical and horizontal. This is like the cat being in a superposition of being both dead and alive. This simple superposition is time-independent, it doesn't "smear". The photons stays this way until they're passed through yet another polarizing filter, say, a horizontal one. Photons coming through this one are now only in the horizontal state, they are no longer in a superposition of two states. LIkewise, once the cat is "observed" to be either dead or alive, by means that is able to distinguish between the two, the cat will now EITHER be dead OR alive, and will no longer be in a superposition both states, nor will "smear" back to such a superposition.

While it's easy to prepare photons in a superposition of two states, it's extradordinarily difficult to prepare a cat in such a superposition of being dead and alive, and there are some reasons to believe that it may be theoretically impossible. The reason for this is that it's difficult to prepare very large objects in a quantum state, so that its wave properties become manifest, even though it's supposed to be theoretically possible. Currently, very "large" objects (still barely visible under a microscope!" are being prepared in a quantum state only under near absolute zero termperatures, because it takes only the slightest disturbance to force a "quantum state reduction", and thereby lose the wave properties.

Answer 2

This is my champion effort. I am not educated on the matter and really only no very little about Schrodinger's cat. You appear to know more then me, but that doesn't mean I can't take a guess.

Look at a different situation rather then the life of a cat in a box. We take death to be an irreversible absolute..... which it is. So assume the two states were looking at are your friend in a box with a 20$ bill that is not his.

When the box is closed, both states exist as one. Your friend has both stolen the 20$ bill and not stolen it. Upon looking inside and viewing the 20$ bill still in sight, become certain that the bill has not be taken, untill you return to the neutral state of both.

Inversly, if you look inside and the bill has been taken, you know the bill has been taken, but it is still a reversable process, unlike death. After a while you can assume guilt or some other force has gotten the best of him and you can return to the neutral state.

Thats only a rough wak at it, I would imagine in the time it took me to write this somone else has already knocked it out of the ball park.

Answer 3

I would tend to believe it is because of entropy.