genericusrnme said:a difference from what?
the 'which-way' information completely changes the state, like the slits be 1 and 2, then you have 1+2 without any information, then 1 OR 2 with information
you can't phase change your way between (1+2),(1),(2)
The "which-way" information refers to the path or trajectory that a particle takes in a quantum system. In quantum mechanics, the act of observing this information can introduce a phase difference, which is a change in the amplitude or energy of the wave function of the particle.
Obtaining "which-way" information can cause a collapse of the wave function, leading to a loss of interference and a change in the behavior of the system. This is known as the "observer effect" in quantum mechanics.
No, according to the Heisenberg uncertainty principle, it is impossible to simultaneously know both the position and momentum of a particle. Therefore, obtaining "which-way" information will always introduce a phase difference in a quantum system.
Yes, the double-slit experiment is a classic example that demonstrates the effect of obtaining "which-way" information on phase difference. When the path of the particle is known, the interference pattern disappears, indicating a phase difference has been introduced.
The presence of an observer is not necessary for the introduction of phase difference when obtaining "which-way" information. Even if the path of the particle is not directly observed, any interaction or measurement of the system will introduce a phase difference due to the uncertainty principle.