Why does 'Quantum Entanglement' kinda contradict 'General Relativity'?
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hey herw is ur answer ....
Historically, the problem was a technical one. After theorists found methods for applying quantum theory to particles (the Schrödinger equation and the Dirac equation) they sought a method for applying quantum ideas to fields (such as the electric field, the weak field, and gravity). They came up with a general way to do that; technically it was called "second quantization." You can read about it in any graduate level textbook on quantum field theory.
But this approach had a serious problem. Many of the calculations gave infinite answers. Schwinger and Feynman and others came up with a way to solve that problem, called "renormalization." In its most simple version, it consisted of separating out the infinite terms, arguing that those are terms that exist even in the absence of the phenomenon that you are interested in, and then throwing them away. It's reminiscent of Dirac saying that the vacuum is full of an infinite sea of negative energy electrons which we never notice; just ignore it and you're OK.
But renormalization failed for gravity. It was related to the fact that to be compatible in the non-quantum limit with general relativity, the exchanged particle in gravity would have to be a spin-two particle, one that we call a graviton. But the renormalization method didn't work.
Nobody ever liked renormalization, but it was very successful. Ignore the infinite part, and you get the right answer! Everyone hoped that eventually we'd look deeper and in the final theory, we would be able to get finite answers without using this cheat.
That is part of the reason for the original excitement over string theory. It gave the same answers as quantum field theory, but without the need for renormalization. Wow! But was it the right theory? It had lots of other problems. But gravity did not seem to be one of them; it appeared to be a natural part of the theory.
As readers of my other writings on Quora know, I am not a fan of string theory. But I was for a while. The avoidance of renormalization struck me as a very strong reason to think that string theory was on the right track. But now I believe that track was wrong. String theory has made too many predictions (particularly for supersymmetric particles) that have turned out to be wrong, and it failed to predict dark energy. Witten claims that it did make a correct prediction: the existence of gravity. But, of course, that was not a prediction; since gravity was already known to exist, I might call it a postdiction.
I suspect that someday we will find a different approach that avoids renormalization, one that will turn out to be the correct approach. My own suspicion: it will be some new variation of string theory that avoids the use of supersymmetry. I'll happily accept any theory that actually makes verifiable predictions that turn out to be correct.
hope u like it and it will help u alot
Historically, the problem was a technical one. After theorists found methods for applying quantum theory to particles (the Schrödinger equation and the Dirac equation) they sought a method for applying quantum ideas to fields (such as the electric field, the weak field, and gravity). They came up with a general way to do that; technically it was called "second quantization." You can read about it in any graduate level textbook on quantum field theory.
But this approach had a serious problem. Many of the calculations gave infinite answers. Schwinger and Feynman and others came up with a way to solve that problem, called "renormalization." In its most simple version, it consisted of separating out the infinite terms, arguing that those are terms that exist even in the absence of the phenomenon that you are interested in, and then throwing them away. It's reminiscent of Dirac saying that the vacuum is full of an infinite sea of negative energy electrons which we never notice; just ignore it and you're OK.
But renormalization failed for gravity. It was related to the fact that to be compatible in the non-quantum limit with general relativity, the exchanged particle in gravity would have to be a spin-two particle, one that we call a graviton. But the renormalization method didn't work.
Nobody ever liked renormalization, but it was very successful. Ignore the infinite part, and you get the right answer! Everyone hoped that eventually we'd look deeper and in the final theory, we would be able to get finite answers without using this cheat.
That is part of the reason for the original excitement over string theory. It gave the same answers as quantum field theory, but without the need for renormalization. Wow! But was it the right theory? It had lots of other problems. But gravity did not seem to be one of them; it appeared to be a natural part of the theory.
As readers of my other writings on Quora know, I am not a fan of string theory. But I was for a while. The avoidance of renormalization struck me as a very strong reason to think that string theory was on the right track. But now I believe that track was wrong. String theory has made too many predictions (particularly for supersymmetric particles) that have turned out to be wrong, and it failed to predict dark energy. Witten claims that it did make a correct prediction: the existence of gravity. But, of course, that was not a prediction; since gravity was already known to exist, I might call it a postdiction.
I suspect that someday we will find a different approach that avoids renormalization, one that will turn out to be the correct approach. My own suspicion: it will be some new variation of string theory that avoids the use of supersymmetry. I'll happily accept any theory that actually makes verifiable predictions that turn out to be correct.
hope u like it and it will help u alot
aree bhai
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