Shrodingers cat - what does it mean?

Question

I have a bit of a grasp of shrodingers cat, anyone wanna properly explain it to me in simple terms?

Answer 1

Schrödinger's cat is a seemingly paradoxical thought experiment devised by Erwin Schrödinger that attempts to illustrate the incompleteness of an early interpretation of quantum mechanics when going from subatomic to macroscopic systems. Schrödinger proposed his "cat" after debates with Albert Einstein over the Copenhagen interpretation, which Schrödinger defended, stating in essence that if a scenario existed where a cat could be so isolated from external interference (decoherence), the state of the cat can only be known as a superposition (combination) of possible rest states (eigenstates), because finding out (measuring the state) cannot be done without the observer interfering with the experiment — the measurement system (the observer) is entangled with the experiment.

The thought experiment serves to illustrate the strangeness of quantum mechanics and the mathematics necessary to describe quantum states. The idea of a particle existing in a superposition of possible states, while a fact of quantum mechanics, is a concept that does not scale to large systems (like cats), which are not indeterminably probabilistic in nature. Philosophically, these positions which emphasize either probability or determined outcomes are called (respectively) positivism and determinism.

Answer 2

Quantum theory assigns probabilities of events happening. For example, finding an electron at a certain radial distance from the nucleus of an atom has a probability attached to it. So in a hydrogen atom, while the mean value of the electron's radius is the Bohr radius, it can literally be anyway in space at given moment, it just may have a very low porbability of happening.

Now quantum mechanics says that until someone makes an observation of the system in question, you don't know what state the system is in. For instance, you don't know how far away an electron is from the nucleus of a hydrogen atom until you try to measure it.

Now Einstein never liked this feature of quantum mechanics so he posed the following dilemma. You place a cat in sealed box. IN the box is a vial of poison gas and a radioactive isotope. The radiation is measured by a counter which, when it i reaches some preset number, cause the vial to be broken and the poor cat to be gassed. Now you can't see into the box or hear noises coming from the box. Since the process of radioactive decay is quantum mechanical, you can't tell for certain whether the counter has reached the fatal number or not. As long as you don't open the box, the cat is both dead and alive ( non-zero probabilities for each). Only by opening the box will you know if the cat has survived or not.

Now the objection is that you are either alive or dead - not both at once. But since there is a quantum mechanical event detyermining the outcome of the system (cat+gas+radioisotope decay), the state of the cat becomes indeterminant - you can't make a definite statement until the box is opened.

Answer 3

Basically it proposes a thought experiment (one not really to be done, but thought about) where a cat is in a closed box where it cannot be seen, along with a capsule of poison gas that will be opened when a single radioactive atom emits a particle of radiation. When it does, the cat dies. The question is, when does the cat die? We know only statistically how long, on average, it would take for the atom to decay and release the gas, but there is a chance it could be any amount of time. Statistically, the longer the cat is in the box, the more likely it is dead, but we don't know for sure until we open the box. Schrödinger proposes a 3rd state, where the cat is not dead and not alive but in some kind of zombie state or whatever, until we open the box and look, then it is either dead or alive.

I never liked Schrödinger's cat. It is just a different way of saying that when a tree falls in a forest with nobody there to hear it, it makes no sound, which I say is not true.

Answer 4

The cat they are talking about is one that is enclosed is a box with litle means to survive. This was a quantum mechanics experiment that should have should never have been formulated in which they argue about what are the probability that the cat is alive or dead or both at the same time. Because according the theory of evolution the cat was not fit to survive in those conditions. And there really was no question about the probability whether after such a long time that he would be dead or alive. Any vet would tell you that the Cat left with litlle air would no longer meow and conclude that he is 100%Dead.
Beside such experiment is cruelty to animals.
This was the silliest thought experiment ever devised.

Answer 5

Basically what he is saying is that we cannot possibly know what is actually happening in an isolated enrivonment, such as a cat being in a room without us being able to see it. We cannot know this because just the very action of VIEWING the experiment will have an effect on the outcome. This is also why we cannot physically see subatomic particles in a given location. The photons that bounce off the particles and reflect back to our eyes is enough to effect the particle and push it around. Like I said before, the very act of looking at something can have an effect on it.

That being said, the cat will be in, what is thought, a suspended state. It is neither dead nor alive. It only BECOMES dead or alive once our eyes view it.

Answer 6

The folks above have said it more eloquently, but basically: If you measure and/or locate a particle, you've changed it's properties, so the particle is no longer behaving the way it was when you wished to take the measurement.

A cat is in a box. It may be alive, or dead, it might be on the left side, or right side - but the *system* of the cat in the box is behaving in a particular way. If you open the box, you break the system, and it no longer behaves in the manner you wanted when you try to measure it.

In essance: You can have the system behave properly, OR you can measure it's components, but you can't do both.

Answer 7

Schroedinger's Cat is really nothing more than a real-world thought experiment concerning one of the rules of quantum physics which states that you can measure the velocity of a subatomic particle and you can measure the position of a subatomic particle, but you can never measure both the position *and* velocity of such a particle at the same instant.

Answer 8

In quantum mechanics, it is used to describe the term indeterminate. The cat is neither dead nor alive, and we can only find out by the standard measure of observing which collapses the wavefunction.

Answer 9

To help sum up "Dan E"s very good explanation, the cat could be said to be BOTH alive AND dead, until the box is opened, and the observer could make that determination.

Answer 10

Every entity in the universe has a zero time reference each is isolated from all others by time.
Even if you can see an entity it is in the past and you can't be sure it still exists.