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ahmad2l
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what is differences between collapse,reduction, decoherence , weak projection and strong projection in quantum measurement theories?
Simon Bridge said:They are different words for describing different ideas about QM.
i.e. "collapse" refers to the way the wavefunction changes once a measurement has been made.
Looking up the definitions of the terms should give you a good idea. What did you find?
In the Schrödinger picture, a time dependent state ket gets projected onto a time independent eigenket of the observable. In the Heisenberg picture, this time (in)dependency is reversed.naima said:According to Schrodinger the state vector evolves with time and collapse is a jump to another temporal curve. I never found a corresponding description in Heisenberg picture.
Simon Bridge said:So you already knew the answer - well done!
StarsRuler said:No, it didn´t know the answer, it is a typical situation people asking on a forum not know the answers to them. And it is typical too that people that write is to answer it. Maybe you could try it sometime, Simon.
On the contrary, it is very common that people pose questions when they do know the answer - they may not realize they knew all along or lack confidence in their knowledge and just need help making the connection.No, it didn't know the answer, it is a typical situation people asking on a forum not know the answers to them.
...please read post #2 (above) and check the author credit. Thank you.And it is typical too that people that write is to answer it. Maybe you could try it sometime, Simon.
Yes, simply use the time-dependent eigenstates (of O2) I talked about in my previous post.naima said:At time t = 0 suppose i find that an obervable O1 has a given value. time goes from 0 to t, O1 (0) evolves to O1 (t) and i make another mesurement. Can i avoid to return to Schrodinger point of view to find the probabilities for each eigenvalues of O2?
Quantum measurement is the process of determining the state of a quantum system by interacting with it. This interaction causes the system to be in a particular state, known as the "collapsed" state.
Collapse is a term used to describe the sudden change in the state of a quantum system when it is measured. In quantum mechanics, the state of a system is described by a wave function, and the act of measurement causes the wave function to "collapse" into a specific state.
Reduction refers to the collapse of the wave function into a particular state during measurement, while decoherence refers to the loss of coherence between different states of a quantum system. Decoherence is caused by interactions with the environment, which can cause the wave function to "blur" and make it difficult to determine the state of the system.
In weak measurement, the interaction with the quantum system is minimal, and the measurement does not significantly affect the state of the system. In strong measurement, the interaction is more significant, and the measurement causes a significant change in the state of the system.
The observer effect refers to the idea that the act of observing a system can affect the system itself. In quantum mechanics, measurement is considered a form of observation, and it has been shown to have a significant impact on the state of a quantum system. This is because the measurement process causes the wave function to collapse, and the act of observation is an essential part of this process.