Title: quantum mechanics - Observer effect, do this mean literally someone or just any interaction with other matter? - Physics Stack Exchange
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Observer effect, do this mean literally someone or just any interaction with other matter?
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Content: Whether a particle that is not interacting with anything undergoes changes in state? Though now that confuses me too, If it is in two states at once. What denote say spin to the left from spin to the right, what denotes the origins of the calculations we make? quantum-mechanics measurement-problem observers
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edited Apr 10 '13 at 21:23
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asked Apr 10 '13 at 21:05
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"Observation" means interaction with anything, which might be a sentient being or might simply be matter. At very small scales (sub-atomic) particles can exist in several states at once. When they interact with anything else - even as small as another electron - they can experience "wavefunction collapse". A "wavefunction" in quantum mechanics is the maths used to describe how something behaves (and that means everything, though there is no point trying to work out a wavefunction for say a bus, as it would be a) impossibly complex, and b) quantum effects are so unlikely and so minuscule at that scale as to be irrelevant, so physicists only talk about wavefunctions for tiny things, such as an electron). The point of these wavefunctions is to describe the world in terms of probability - for instance, one cannot talk about an electron being in a particular place, but rather only of the probability of it being there. (this is entirely different from the uncertainty principle. That states that certain complementary metrics cannot be known with complete accuracy at small scales.