Wave functions and the cat!!!?

You have to keep in mind that a quantum particle is in fact "something" between a particle and a wave. The information of that quantum particle is coded in its quantum wave function.

A classical cat is always in a well defined unique state: alive or dead.

On the other side the Schrodinger cat is a quantum pet, and a quantum particle can be in a superposed state (the state of the particle is not necessarily simple!). It's wave function is a superposition of two states |alive> and |dead>. Then as a free particle this cat can be both alive and dead which is shocking at our classical level...

But when you try to observe this quantum particle you always interact, even slightly, with it (for example by pointing light on it). This interaction induces changes in the phase wave of the pseudo particle. Then, at the end this interaction projects the particle into a defined state. At the microscopic level a particle does not behave as a classical one, but it has to be seen as a complex information (quantum wave function) interacting with other surrounding wave functions... A quantum particle is never totally free then it's quantum state can always be influenced by its environment (interaction with matter, radiation, ...)

The shrodinger's cat is a thought experiment dealing with the issue of measurement in quantum mechanics. Once the observation is made, for exemple in the slits experiments, the photon still behaves as a quantum particle but its wave function is now reduce to a less complex one.

Hope this helps you

Schrodinger’s Cat IV

'I think it is safe to say that no one understands quantum mechanics'. Richard Feynman

If anyone understood QM it would be Richard Feynman

We don’t “understand” QM, we”interpret” it. We form mental pictures of what is going on and those pictures are weird because QM is weird. There are over 20 equally valid interpretations of QM. The Copenhagen Interpretation on which Schrodinger’s Cat is based is just 1 of those interpretations. It is very unlikely that any of the interpretations are “Reality.” So the whole Schrodinger’s Cat position that a cat can be both alive and dead at the same time is based on what is very likely a false premise (Copenhagen is reality). The most likely reality is: The cat is alive or dead and we cannot know until we look.

“By 1928 or so, many of the mathematical formulas and rules of quantum mechanics had been put in place and, ever since, it has been used to make the most precise and successful numerical predictions in the history of science. But in a real sense those who use QM find themselves following rules and formulas laid down by the ‘Founding Fathers’ of the theory…. Without really understanding why the procedures work or what they really mean. ….

What are we to make of all this? Does it mean that on a microscopic level the universe operated in ways so obscure and unfamiliar that the human mind, evolved over eons with phenomena on familiar everyday scales, is unable to fully grasp what really goes on? Or, might it mean that through historical accident physicists have constructed an extremely awkward formulation of QM that, although quantitatively successful, obfuscates the true nature of reality? No one knows.” – Brian Greene, The Elegant Universe

What happens to the cat is widely debated. Since the issue cannot be resolved without violating Indeterminacy, we will probably never know. There are 3 general positions on what happens.

1. The cat is a macro entity. As such QM does not apply. ===> The cat is either alive OR dead. (Schrodinger’s position) We find out when we look.

2. The Copenhagen Interpretation of QM applies. ==> The cat is both alive and dead at the same time. The cat’s Psi function collapses to alive or dead when we look.

3. Many Universe Interpretation of QM applies. ==> There are 2 universes. In one universe the cat is alive. In the other universe the cat is dead. We find out which universe we live in when we look.

OPINION: The whole issue is moot. The Geiger counter and cat’s body are observers that collapse the PSI Function for the system. We don’t know what happened, but the Geiger counter (If decay occurred, the Geiger counter took action to kill the cat.) and cat body do know (The cat died). The system is never “Indeterminate.”

Schrodinger Cat is useful as a test thought experiment to differentiate between the 20 or so interpretations of quantum mechanics. Example:

Google "Quantum Suicide/Immortality" the thought experiment has a different outcome depending on if you use Many Worlds or Copenhagen to analyze what happens if you try to commit suicide with a gun

that is quantum state controlled.

"All of quantum mechanics is contained in the 2-Slit Experiment" - Richard Feynman Even if we run the experiment 1 photon at a time, the photons still collect in the same fringe pattern predicted by the wave equations. We cannot argue that different photons interfered, each photon had to go through both slits (or information about each photon went through both slits.)