- #1
Blue Scallop
- 290
- 17
This is related to vanhees71 statements (see bottom). I'll explain.
First. The idea is very simple. As summary: Einstein showed that if reality was objective and quantum theory complete, then there had to be nonlocal effects. But since nonlocal effects can violate relativity, then there had to be hidden variables (insert the EPR arguments here about measurement position and momentum of the two entangled particles which I don't want to detailed again)
Now enter Bell's Theorem. I read in a bell book "Bell wanted to see what the quantum world would be like if local hidden variables really existed - and here the word "local" is important. Local hidden variables refer to physical quantities which locally determine the state of an object inside an imaginary surface. By contrast, nonlocal hidden variables could be instantaneously changed by events on the other side of the universe. Assuming that any hidden variables are "local" is the assumption of local causality. Using this assumption, Bell derived a mathematical formula, an inequality, which could be checked experimentally. The experiment has been done independently at least half a dozen times, and Bell's inequality - along with its central assumption of local causality - was violated. The world, it seemed, we as not locally casual!"
Of course it doesn't mean we can send signal faster than light. Bell's equality violation is due to very detailed nature of the Clauser and Aspect experiments which showed that when the polarization of A is changed, somehow B is correlated. If wave function is ontic or objective, then there may be non-local hidden variables. If wave function is epistemic, then the correlations are in the equations yet there are still distant correlations via the equations. This is in contrast to the arguments about blue and red socks being determined from the beginning. For this message. let's assume the wave function is epistemic and the correlation occur via the equation even light years apart.
Now enter Vanhees71. I've been analyzing his thoughts for many days. It's important because he is one of the most powerful physicists around in the sense that he represents the rest of the physicists who don't care about interpretations and only lab results. There is nothing wrong with this.. but I think there is big possibility he hasn't really understood the exact setup for the Clauser and Aspect experiments.. so he argued there was correllation but it occurred in the initial preparation just like the blue and red socks arguments.
This is very important to scrutinize because vanhees71 has been describing it for 7 years and the purpose of physicsforums is to educate.. but somehow some of us get quite confused by his arguments that don't conform to the mainstream idea of Bell's experiments. Ok here's the proof. I read all his messages about Bell's Theorem and the following summarized his views. Vanhees71 states:
"It is very important to distinguish between nonlocal interactions (which are by construction not present in standard relativistic QFT) and longranged correlations, which are a specific consequence of any quantum theory, including relativistic QFT. It is not that measurement of one photon's polarization in an entangled two-photon state that causes the correlation but the preparation of the entangled two-photon state in the very beginning of the experiment. Although the single-photon polarizations are maximally indetermined, the 100% correlation between them is there all the time due to the preparation procedure in an entangled state. There is no non-local interaction between the single photons and the polarizers and photo detectors at A's and B's far-distant locations whatsoever! Consequently, according to local relativistic QFT it cannot be nonlocal interactions caused by the local measurements at the local detectors. This shows that these experiments do not contradict standard QED and thus there's no need for nonlocal interactions!"
Reference: Msg 21 of https://www.physicsforums.com/threads/collapse-of-a-wave.845613/page-2#post-5309489
But Clauser and Aspect experiments showed changing A can somehow affect B when comparing the notes later.. as if the correlation is in the equations (that is, even if wave function is not objective and there is no non-locality.. no problem with this as the correlations can occur in the equation).. this means even when light years apart.. the statistics of each can be affected what one does in the other end.. while Vanhees71 arguments is they never do and the long distant correlation is in the initial preparation..
Am I wrong or Vanhees71 wrong? If Vanhees71 is right, and the correlation is due to the initial preparation.. but doesn't this go against the results of the Crauser and Aspect experiments? Please tell me what is the case. Thank you.
First. The idea is very simple. As summary: Einstein showed that if reality was objective and quantum theory complete, then there had to be nonlocal effects. But since nonlocal effects can violate relativity, then there had to be hidden variables (insert the EPR arguments here about measurement position and momentum of the two entangled particles which I don't want to detailed again)
Now enter Bell's Theorem. I read in a bell book "Bell wanted to see what the quantum world would be like if local hidden variables really existed - and here the word "local" is important. Local hidden variables refer to physical quantities which locally determine the state of an object inside an imaginary surface. By contrast, nonlocal hidden variables could be instantaneously changed by events on the other side of the universe. Assuming that any hidden variables are "local" is the assumption of local causality. Using this assumption, Bell derived a mathematical formula, an inequality, which could be checked experimentally. The experiment has been done independently at least half a dozen times, and Bell's inequality - along with its central assumption of local causality - was violated. The world, it seemed, we as not locally casual!"
Of course it doesn't mean we can send signal faster than light. Bell's equality violation is due to very detailed nature of the Clauser and Aspect experiments which showed that when the polarization of A is changed, somehow B is correlated. If wave function is ontic or objective, then there may be non-local hidden variables. If wave function is epistemic, then the correlations are in the equations yet there are still distant correlations via the equations. This is in contrast to the arguments about blue and red socks being determined from the beginning. For this message. let's assume the wave function is epistemic and the correlation occur via the equation even light years apart.
Now enter Vanhees71. I've been analyzing his thoughts for many days. It's important because he is one of the most powerful physicists around in the sense that he represents the rest of the physicists who don't care about interpretations and only lab results. There is nothing wrong with this.. but I think there is big possibility he hasn't really understood the exact setup for the Clauser and Aspect experiments.. so he argued there was correllation but it occurred in the initial preparation just like the blue and red socks arguments.
This is very important to scrutinize because vanhees71 has been describing it for 7 years and the purpose of physicsforums is to educate.. but somehow some of us get quite confused by his arguments that don't conform to the mainstream idea of Bell's experiments. Ok here's the proof. I read all his messages about Bell's Theorem and the following summarized his views. Vanhees71 states:
"It is very important to distinguish between nonlocal interactions (which are by construction not present in standard relativistic QFT) and longranged correlations, which are a specific consequence of any quantum theory, including relativistic QFT. It is not that measurement of one photon's polarization in an entangled two-photon state that causes the correlation but the preparation of the entangled two-photon state in the very beginning of the experiment. Although the single-photon polarizations are maximally indetermined, the 100% correlation between them is there all the time due to the preparation procedure in an entangled state. There is no non-local interaction between the single photons and the polarizers and photo detectors at A's and B's far-distant locations whatsoever! Consequently, according to local relativistic QFT it cannot be nonlocal interactions caused by the local measurements at the local detectors. This shows that these experiments do not contradict standard QED and thus there's no need for nonlocal interactions!"
Reference: Msg 21 of https://www.physicsforums.com/threads/collapse-of-a-wave.845613/page-2#post-5309489
But Clauser and Aspect experiments showed changing A can somehow affect B when comparing the notes later.. as if the correlation is in the equations (that is, even if wave function is not objective and there is no non-locality.. no problem with this as the correlations can occur in the equation).. this means even when light years apart.. the statistics of each can be affected what one does in the other end.. while Vanhees71 arguments is they never do and the long distant correlation is in the initial preparation..
Am I wrong or Vanhees71 wrong? If Vanhees71 is right, and the correlation is due to the initial preparation.. but doesn't this go against the results of the Crauser and Aspect experiments? Please tell me what is the case. Thank you.