New answers tagged

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In addition to the issue that others have mentioned of observing the photon near the slit, there is the issue of observing the interference pattern. What experimental set up would allow two people to see two different patterns? If both observers are watching the screen they will both see the same pattern. I say "see", but actual vision would ...


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I agree with the answer by m2cts, and here is an experiment that confirms the statements: Electron buildup over time Electrons are fired on the double slit one at a time. In frame a) the individual footprints of the electrons are seen on the screen, and they look random and like footprints of particles, no fudge or spread in space. So a single electron has ...


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To add to some other answers. Being able to tell that someone has tampered with the photon is a key aspect of secure quantum communications. No communications system is totally secure from eavesdropping, but it is good to know whether a given communication has been intercepted. The most advanced quantum-encrypted communications links monitor the states of ...


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The quantum mechanical description of the double slit experiment is as follows: If the particle passes through the left slit it is described by the wave function $\psi_{l}$. If the particle passes through the right slit it is described by the wave function $\psi_{r}$. If it is impossible to know through which slit the particle passes, we have to account ...


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Neither the particle not the observer "interferes with itself" . The parts of the wave function passing through each slit interfere. The resulting interference pattern gives the probability of finding a particle. If the two parts of the wave function, left and right, are made distinguishable by a detector, they become mutually orthogonal or ...


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The term 'observe' does not mean watching the experiments from a camouflaged hideout so that no one notices you are there. 'Observe' here means 'making a measurement' and hence interacting with the system. The result of this interaction is the wavefunction collapse, a type of time-evolution that is not accounted for within the current quantum mechanical ...


2

Heisenberg himself, who discovered the uncertainty principle, originally thought it was a measurement issue, just as Hawking describes it. As time went by, it was found to explain many phenomena unrelated to measurement as such. For example it is what allows virtual particles to exist for fleeting moments of time - by definition not long enough to be ...


4

I generally have a problem with such "intuitive" explanations of the Uncertainty Principle, as I feel that they create more problems than they solve. Don't get me wrong: it's certainly a very useful way to introduce the topic to the uninitiated, since going into detail about wave functions and non-commutativity of operators representing physical ...


4

Physics is a mathematical description of the behavior of the universe. The uncertainty principle is written as it is to describe the physical behavior. So it is a physical consequence. But it is also a consequence of the math, because the math matches the physical behavior. It is not a coincidence. The math was purposely written that way. Given the close ...


3

If the uncertainty relation is a physical consequence of a theory, we have not found why or how, at least in general. The uncertainly relation applies to any pair of (usually non-commuting) operators, even some which have limited physical interpretation, like $(x+p)^3$ and $(x^2-p)^7$, or even to totally abstract operators which are general functions of ...


3

Hawking clearly stated it as a physical consequence, which is more intuitive than the mathematical one. In general in physics, laws, postulates, principles are distillates of a large number of observations. The mathematical models and the solutions are chosen so that these laws, principles, postulates are obeyed. Finally, my question is which one of the ...


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There is Glick & Adami's paper, also with a less formal summary there goes the Copenhagen Interpretation. Which after all, also means so to goes objective collapse - and many worlds. "So your math says that wavefunctions don't collapse. Can you prove it experimentally?" Basically, G&A outline with information theoretic fashion that ...


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In quantum mechanics, a particle is neither a wave nor a particle but is described by a wave function which does not have a physical interpretation Note the bold a particle. The quantum mechanical equations , Dirac, Klein Gordon, quantized Maxwell, all describe a single particle. The postulates of Quantum Field Theory are the postulates of Quantum mechanics,...


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If by "objective" you mean "real", a wave function, $Ψ$ is only mathematically fundamental because it is a postulate of quantum mechanics, a function of complex numbers, it cannot be measured independently. Only $Ψ^*Ψ$ is a measurable prediction as the probability distribution. This allows different formats for $Ψ$, that can give the ...


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The proposition "The wavefunction is all there is" is meant to clarify the difference between the many-worlds theory of quantum mechanics and some other quantum mechanical interpretations. In many other interpretations there are additional physical laws required to explain what happens during a measurement. In those interpretations there is, in ...


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