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jebii
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Forgive me if this is a dumb question; from what I've been reading an electron can exist simultaneously in two places. Is this definite?
Why can/can't it exist in more forms?
Why can/can't it exist in more forms?
jebii said:Forgive me if this is a dumb question; from what I've been reading an electron can exist simultaneously in two places. Is this definite?
Why can/can't it exist in more forms?
haael said:Everything depends on what you mean by "electron". If you think of it as "tiny charged ball", then you indeed will need to assume it is in 2 different places.
Vanadium 50 said:Please read bhobba's answer. QM gives an unequivocal answer to this question, and that answer is "no".
akhmeteli said:However, strictly speaking, we can never say that an electron was at time t0 at point x0, as no position measurement can be infinitely precise due to the uncertainty principle: infinitely precise position measurement at a certain moment in time would require infinite energy.
Vanadium 50 said:QM gives an unequivocal answer to this question, and that answer is "no".
The general principle of superposition of quantum mechanics applies to the states [that are theoretically possible without mutual interference or contradiction] ... of anyone dynamical system. It requires us to assume that between these states there exist peculiar relationships such that whenever the system is definitely in one state we can consider it as being partly in each of two or more other states. The original state must be regarded as the result of a kind of superposition of the two or more new states, in a way that cannot be conceived on classical ideas. Any state may be considered as the result of a superposition of two or more other states, and indeed in an infinite number of ways. Conversely any two or more states may be superposed to give a new state...
Ravi Mohan said:I am little confused. In principles of Quantum Mechanics, Chapter 1 section 4, Paul Dirac writes
bhobba said:A lot of water has gone under the bridge since Dirac wrote that classic.
It's well known there are a number of mistakes and misconceptions in that book.
If you want to understand the modern view see Ballentine.
The above is one of that books misconceptions, and its not the only one.
Ravi Mohan said:I think, please correct me if I am wrong, the meaning of superposition depends on the interpretation we choose.
Ravi Mohan said:If we assume that [itex]|\Psi\rangle[/itex] provides a complete and exhaustive description of an individual system, then superposed states imply the existence of system in two or more states.
Ravi Mohan said:But if we assume that a [itex]|\Psi\rangle[/itex] describes the statistical properties of an ensemble of similarly prepared systems, then the superposition of states is simply a different description of the ensemble.
Ravi Mohan said:My point is that QM is silent on the meaning of superposition. If we follow certain interpretation, then the answer to the OP's query could be affirmative.
Yes sir. I read your reply. I was trying to put my views on why I think that Dirac's statement is correct and makes sense.bhobba said:Precisely. Note carefully what I said in my reply. It was about the FORMALISM.
Ravi Mohan said:To be sure, which interpretation does Dirac follow in Principles of Quantum Mechanics?
Vanadium 50 said:Please read bhobba's answer. QM gives an unequivocal answer to this question, and that answer is "no".
akhmeteli said:I don't know. My impression was that, say, diagram (b) at https://www.llnl.gov/str/May06/Beiersdorfer.html is part and parcel of a physical electron, so you can detect two electrons with energetic enough photons where there is actually just one physical electron. Am I wrong?
Drakkith said:That is absolutely incorrect. You will only ever detect one electron.
bhobba said:Just reviewing my posts and I see I forgot to mention exactly what was Dirac's misconception.
Its not what he said was wrong, its what he didn't make clear - namely the state he is talking about does not necessarily exist in a real sense. When you read it you naturally assume, like the states of classical physics, its real and that's where the problem arises. You think that, for example, if you are considering a state whose observation will give say position A or B, and from the principle of superposition that can be considered a superposition of a state that when observed will definitely give A and one that will definitely give B, then literally it is two positions at once. But since a state in QM is like probabilities, not real in any usual sense, it doesn't have to be viewed that way. Its like if you toss a coin you know it will give a head or tail but while its spinning in the air you can't say its both a head and a tail at the same time - all you can say is its spinning. The same in QM - just because you know you will get A or B if you observe it you can't say it's both A and B when you are not observing it.
Thanks
Bill
akhmeteli said:Any arguments?
Ravi Mohan said:While I understand your explanation about superposition of two states not implying the existence of the particle in those two states, I would like to direct attention towards the literature of gravity induced collapse models.
Yes, according to the principles of quantum mechanics, an electron can exist in multiple places at the same time. This is known as superposition, where the electron is in a state of being both here and there until it is observed or measured.
The concept of an electron being in multiple places at once is a result of the wave-like behavior of particles at the quantum level. The electron is not a solid object, but rather a probability wave that can exist in all possible locations until it is observed.
No, this phenomenon of superposition is not limited to electrons. Other subatomic particles, such as protons and neutrons, can also exhibit this behavior. Even larger objects, such as molecules, have been observed to exist in multiple places at once.
Superposition is a fundamental principle of quantum mechanics and is crucial in understanding the behavior of matter at the atomic and subatomic level. It has also led to the development of technologies such as transistors and lasers, which are essential components of modern electronics.
While superposition has been observed in various experiments, scientists have not yet found a way to control or harness this phenomenon for practical applications. However, ongoing research in the field of quantum computing aims to utilize superposition to create more powerful and efficient computers in the future.