Sözler ve Alıntılar
Superposition
So what we really have is a superposition of all possible combinations of where the electron might have been located, and where the camera actually observed it to be.
Hidden variables
But Bell’s theorem implies that any such theory requires “action at a distance”—a measurement at one location can instantly affect the state of the universe arbitrarily far away. This seems to be in violation of the spirit if not the letter of the theory of relativity, which says that objects and influences cannot propagate faster than the speed of light. The hidden-variable approach is still being actively pursued, but all known attempts along these lines are ungainly and hard to reconcile with modern theories such as the Standard Model of particle physics, not to mention speculative ideas about quantum gravity, as we’ll discuss later. Perhaps this is why Einstein, the pioneer of relativity, never found a satisfactory theory of his own.
When you perform a measurement, such as the position or spin of a particle, quantum mechanics says there are only certain possible results you will ever get. You can’t predict which of the results it will be, but you can calculate the probability for each allowed outcome.
Quantum mechanics isn’t magic. It is the deepest, most comprehensive view of reality we have. As far as we currently know, quantum mechanics isn’t just an approximation of the truth; it is the truth.
Copenhagen interpretation
In a modern university curriculum, when physics students are first exposed to quantum mechanics, they are taught some version of these five rules. The ideology associated with this presentation—treat measurements as fundamental, wave functions collapse when they are observed, don’t ask questions about what’s going on behind the scenes—is sometimes called the Copenhagen interpretation of quantum mechanics. But people, including the physicists from Copenhagen who purportedly invented this interpretation, disagree on precisely what that label should be taken to describe. We can just refer to it as “standard textbook quantum mechanics.”
Quantum systems are described by wave functions rather than by positions and velocities. Just as Newton’s laws of motion govern the evolution of the state of a system in classical mechanics, there is an equation that governs how wave functions evolve, called Schrödinger’s equation. We can express Schrödinger’s equation in words as: “The rate of change of a wave function is proportional to the energy of the quantum system.”
On the other hand, in the memorable words of Richard Feynman, “I think I can safely say that nobody understands quantum mechanics.” We use quantum mechanics to design new technologies and predict the outcomes of experiments. But honest physicists admit that we don’t truly understand quantum mechanics.