has a few hours left, and Nobel Prize in Physics will be announced. Here I will make a small prediction. I think this year's Nobel Prize will be awarded to Aspect, Clauser and Zeikinger because of their contribution to the Bell inequality verification - this result is really important. Their work declared to Einstein - Sorry Mr. Einstein, you are really wrong in quantum mechanics !
Although Einstein proposed the concept of " light quantum " and fired the starting gun of the quantum mechanics revolution; however, he did not support the interpretation of quantum mechanics by the Copenhagen School founded by Bohr , so he has been looking for loopholes in the Copenhagen School's theory. In the quantum mechanic interpretation of the Copenhagen school, there is a strange thing called the uncertainty relationship. According to the uncertain relationship, the position and momentum of a microscopic particle cannot be accurately determined at the same time. If the momentum of the particle is determined accurately, the position cannot be determined at all; and if the position can be determined accurately, the momentum cannot be determined at all. This time, Einstein attacked the uncertainty relationship.
Uncertainty Relationship
In that article titled "Can you think that quantum mechanics' description of physical reality is complete? In the paper 》, Einstein, Podolsky and Rosen (E, P, and R respectively) designed the famous EPR thought experiment - it was this thought experiment that opened the door for quantum communication for us:
Einstein's EPR paper
For example, there are now two interacting particles that are A/B, and move in two directions after they are separated. Since they are not subjected to external forces, the momentum of these two particles is conserved. When these two particles are far enough, I can accurately measure the momentum pA of particle A, and because of the conservation of momentum, pB=-pA; at this time, Einstein assumes that because these two particles are far enough, the measurement of A will not interfere with B (domain theory). Then if we accurately measure the position xB of particle B at the same time, then we will accurately obtain the position and momentum of particle B at the same time, which violates the uncertainty relationship. Here, Einstein made the assumption of the localization theory, that is, when A/B particles are infinitely far apart, observations of one particle will not have any impact on the state of another particle.
This issue attracted great attention from Bohr, and he put down almost all his work to think about this issue. Five months later, in the same magazine, Bohr published a response, and even used the exact same title to confront each other - "Can you think quantum mechanics' description of physical reality is complete? 》.
Bolhr's refutation paper
Generally speaking, Bohr refuted the EPR paradox from three aspects.
1. Reiterates the meaning of "physical truth", that is, only what is observed can be said to be physically true;
2. It shows that observations will definitely affect other variables in the system (if the two variables are inconsistent);
3. It shows that even if the two particles are infinitely far apart, the observation of one of the particles will affect the state of the other particle - that is, the localization theory is not valid.
Einstein was not satisfied with Bohr's explanation, especially point 3. Intuition tells us that both particles are already infinitely far away, and will the measurement of one of them affect the other? Could this be the that acts as over distance? However, until Einstein's death, no one could find the proof method , which verified whether the localization theory was true, so it was impossible to prove which one was right or wrong.
Scientist John Bell agrees with Einstein. Under his active thinking, he proposed the Bell inequality, which can be verified using experiments to prove whether it is an Einstein pair or a Bohr pair. His original intention was to prove that Einstein was right. Unexpectedly, after experiments by Aspect, Clauser, Zeikinger and others, it was found that this inequality proved that Einstein was wrong and Bohr was right. But unfortunately, John Bell has passed away and cannot win the Nobel Prize for .
At the beginning, many Einstein supporters continued to be stubborn - they tried their best to find various possible loopholes. Finally, in the Big Bell Test in 2016, all these possible loopholes were blocked - although Bohr's idea was not in line with our intuition, it was right. In the Big Bell Experiment, more than 100,000 players were summoned around the world to play the game - maybe some readers of this article participated.
So what is the significance of such a proof? On the one hand, this is of great significance to the theoretical basis of quantum mechanics. On the other hand, you may have heard that my country's Academician Pan Jianwei has achieved pioneering results in the field of quantum communication . Compared with traditional communication methods, quantum communication cannot be monitored and information cannot be stolen, which is a truly safe communication method. And it is precisely because Bohr is right that quantum communication can be made possible.
Academician Pan Jianwei's paper on quantum communication was published in the journal Science
Quantum entanglement
