entropy1 said:I was wondering, suppose we have an entangled pair of particles, individually measured at perfectly isolated labs (with the exception of the incomming particles). Now both researchers are in superposition of having seen their particle detected or not detected or property being up or down or something like that. Now say that they have a classical phone to ring each other. If and when they ring each other and convey the results of their measurements to each other, they now know each other's measurement results and will agree on them. So, are the researches now no longer in superposition? (since the results are in?)
entropy1 said:I know a little of product states, but I can't interpret the ones you gave. Of what are they a product?
Does ##|HH \text{Alice}_H \text{Bob}_H\rangle## mean: both particles in state H and both measurents results are H?
entropy1 said:Now both researchers are in superposition of having seen their particle detected or not detected or property being up or down or something like that. Now say that they have a classical phone to ring each other. If and when they ring each other and convey the results of their measurements to each other...
entropy1 said:So you say "decoherence has occurred". However, when the researches haven't rung each other yet, the measurement results are decohered in the separate individual labs already, aren't they? Yet, in that stage the labs are still in superposition of two results (detected/not deteced/up/down). What is special about the latter decoherence, when the researchers ring each other, that make the results as it were to collapse into a definite shared result?
Do you mean that decoherence destroys superposition?Strilanc said:Decoherence will have occurred as soon as either of the measurements has been done. There's no way to keep the labs isolated in the sense you want.
It's as if you were asking for the experimenters to be wearing socks with identical color and also asking for the colors to be totally unrelated until they called each other on the phone. It makes no sense.
entropy1 said:Do you mean that decoherence destroys superposition?
entropy1 said:Do you mean that decoherence destroys superposition?
The superposition of measurement apparatus is a fundamental principle in quantum mechanics which states that a quantum system can exist in multiple states or positions at the same time until it is observed or measured. This means that a particle can simultaneously be in different places or states until it is observed, at which point it will collapse into a single state.
The uncertainty principle, proposed by Werner Heisenberg, states that it is impossible to know both the position and momentum of a particle with absolute precision. The superposition of measurement apparatus is related to this principle as it explains that the act of measuring one quantity (such as position) will affect the measurement of the other quantity (such as momentum). This is because the act of measuring collapses the particle's superposition into a single state, making it impossible to know the other state with certainty.
Yes, superposition of measurement apparatus has been observed in numerous experiments, most famously the double-slit experiment. In this experiment, a single particle is fired at two slits simultaneously, and it is observed to create an interference pattern on the other side, indicating that it behaved as if it had gone through both slits at the same time. This is only possible if the particle existed in a state of superposition before it was observed.
Superposition of measurement apparatus has the potential to greatly impact technology, particularly in the field of quantum computing. By utilizing the multiple states of a quantum system, quantum computers can perform certain calculations much faster than classical computers. However, maintaining the delicate state of superposition is still a major challenge for scientists.
The superposition of measurement apparatus is mainly observed in the microscopic world of quantum mechanics. While there have been some attempts to observe it in macroscopic objects, such as a mirror or a cat, it is currently not possible due to the fragility of the superposition state. The larger an object is, the more interactions it has with its environment, making it difficult to maintain a superposition state for any significant amount of time.