Could someone explain the Schrodinger's Cat experiment to me?

[Bob_for_short]

This is not necessarily true. You cannot rule out discovering the exact laws of physics and the correct intitial coinditions. ...

Yes, I can. In fact any system is many-particle one. As soon as it is so, it is impossible to reach the absolute accuracy. Take an electron, for example. It is in permanent interaction with the quantized electromagnetic field and there is no a threshold to excite soft photon modes. Thus it is not possible to know everything about the electron.

 

[kote]

Yes, I can. In fact any system is many-particle one. As soon as it is so, it is impossible to reach the absolute accuracy. Take an electron, for example. It is in permanent interaction with the quantized electromagnetic field and there is no a threshold to excite soft photon modes. Thus it is not possible to know everything about the electron.

You are arguing about the practicality of determining initial conditions which is entirely different from the logical possibility that definite initial conditions may exist. CI typically connects the two, but, as Bohm has shown us, QM itself does not necessitate this leap.

 

[Halcyon-on]

In QM there are "observables" that are always the same dispite spreading other "observables". For example, take a monochromatic light in a double-slit experiment. The photon frequencies are the same but positions change from one observation to another. The frequency is the energy, the position spread corresponds to the wave function. The wave function "measurement" needs many experiments. The energy, if it is an eigenvalue, does not need many. The momentum is reciprocal to the position, it is an argument of the wavefunction in the momentum space. In this respect making many measurements to find out the entire wave function does not differ from classical mechanical measurements that need many points for better accuracy (for determinism).

First comment: the energy is the conjugate variable of the time. To determine the energy and the frequency with great accuracy you must observe the wave for a long time, according to Heisenberg.

Second comment: even if you know exactly the wave function using QM you'll never know in which point after the doubleslit the photon will hit. You only know exactly the probabilities.

In a classical statistical theory, in principle, if you know exactly the initial conditions of the particles (suppose a sufficiently simple and not chaotic system), you can predict exactly the evolution also not statistically, particle by particle. This was the illuministic view of the physical world in XIX century, before the quantum revolution. A word made of perfect mechanisms and ball, completely determined by the initial condition.

 

[Bob_for_short]

You are arguing about the practicality of determining initial conditions which is entirely different from the logical possibility that definite initial conditions may exist. CI typically connects the two, but, as Bohm has shown us, QM itself does not necessitate this leap.

Logical possibility arises if we introduce some simplified notions for that. In particular, a sole but observable point-like particle which does not correspond to the experiment. It is our idealisation. It does corresponds to the center of inertia but does not include the internal degrees of freedom (multi-particle nature) of our body.

Ask yourself with what precision the Moon's position may be measured. With the size of the Moon because any point within it belongs to the Moon. But the average may have much less uncertainty.

In CM one often forgets about real sizes and reduces the physics to the center of inertia motion. No wonder such a simplification fails in certain cases.