2022 Nobel Prize in Physics was finally announced on October 4. The winners were Alan Aspe from France, John Crowther from the United States, and Salinger from Austria . These three physicists were confirmed to determine that Bell inequality was not true through photon entanglement experiments, and pioneered the field of quantum information science.
From a certain perspective, the award results are directly to let the public know that Einstein is wrong, why?
Because Nobel Prize was awarded to a quantum entanglement experiment that proved that Bell's inequality was ineffective, and this experiment directly negated Einstein's idea that the realization of localization in the quantum world is still maintained.
EPR paradox
Time went back to 1935, Einstein and his two assistants Podolsky and Rosen published an article titled "Can you think that quantum mechanics 's description of physical reality is complete? 》 paper.
paper content, but its core idea is called the EPR paradox. From the following example, we can understand it in a simple way:
Imagine a pair of entangled particles. If we separate the two from tens of thousands of light years apart, when we measure one of them, for example, particle A is spin-measuring the upper, because the two are in an entangled state, then the B particles in the distance will naturally be spin down.
First of all, Copenhagen interprets that before measuring particle A, it is in a superposition state with both upward and downward spins. Once the measurement behavior is generated, the wave function collapses, and the only measurement result will be obtained, either upward or downward, and the B particles in the distance will also detach from the superposition state at that moment and become a state opposite to the spin of particle A.
Einstein believes that there are loopholes in this process. First of all, it does not recognize that the spin state of the particle needs to be measured before it can be known, because this does not conform to physical reality. The state of the particle should be prepared from the beginning and is certain, just like the moon in the sky. Doesn’t it exist when you don’t look at it?
Secondly, since the spin state has been determined, no matter how far AB is separated, as long as one of the particles is measured, the state of the other particle will naturally be known, just like you open a pair of gloves into two boxes, one box left on Earth, and the other box is placed on Mars. Now the other person only needs to open the Earth box and you can immediately know whether the Mars box is filled with the left glove or the right glove.
In Copenhagen's interpretation, the state of the first two particles is uncertain, and they are in a superposition state. Only when one of the particles is measured can the other particle determine its own state. Einstein believed that this process violated the requirements of localization, that is, there is an information connection between AB particles with superluminal speed . Einstein himself called it "the ghostly super-distance effect ".
- Hidden variable theory
Of course, Einstein's view must have been refuted by the Copenhagen school, and its boss Bolh was naturally the first to stand up. After all, Bohr and Einstein have always competed against this issue.
Bol believes that the quantum phenomenon cannot be distinguished. Even if AB particles are far apart, they are still a whole. The measurement behavior causes the wave function to collapse, which will naturally affect AB particles at the same time. In addition, a physical phenomenon can only be called a phenomenon after measurement. You cannot and cannot know its state before this.
But in any case, Einstein still strengthened his belief that quantum mechanics is incomplete, believing that there should be a more perfect theory above quantum mechanics, called the hidden variable theory, which can eliminate those random uncertainties and then make "God no longer rolls the dice."
Bell inequality
is unfounded. After all, physics is an experimental subject. Is there any way to prove their point of view?
Awesome people appeared. In 1964, British scientist John Stewart Bell proposed a famous mathematical inequality called Bell inequality, and opened the door to the feasibility of the EPR paradox experiment.
This inequality starts from the perspective of classical physics and limits the measurement results of particles separated from each other. Simply put, if the experimental results violate the Bell inequality, then the realization of the realm is self-defeating, and Einstein is wrong.
In order to let everyone understand this Bell inequality in a popular way, let’s show the process in a very simple derivation method:
build a three-dimensional rectangular coordinate system , which has 8 hexagram limits
Then the spin situation of the particle can be included, for example, the split first particle A spin direction is in the first hexagram limit, then from the three axis of XYZ, Ax is +, Ay is +, Az is +, and at this time the spin direction of B particle is obviously opposite, so Bx, By, Bz are all -, and so on. When the spin direction of A is in different hexagram limits, there will be seven next situations with B particles. As shown in the figure
Although I don’t know which result the two particles will be, the probability of these 8 situations being combined is 1. However, when measuring, because there are three directions to choose, the correlation degree of the spin state of the particle can be expressed as Pxy, Pzy, and Pxz. Pxy refers to measuring A particles from the X direction and B particles from the y direction. If the measurement results are consistent, then it is positive, and inconsistency is negative. The equation is written like this Pxy=-N1-N2+N3-N4+N5-N6+N7+N8, and so on, Pzy and Pxz can be written.
After we subtract Pxz and Pzy to get the absolute value, recalling the absolute value in absolute value inequality ||a|-|b|| ≤|a|+|b|, so we can write it out. At this time, we found that these four terms can become bloated. We accidentally found that the sum of the probability of the 8 hexagram limit is 1, and the latter is Pxy
, so we have this inequality. This is the Bell inequality
, the above derivation process is based entirely on classical physics, that is, the result obtained by satisfying the reality of the locality. If the experimental results can verify that this inequality is true, it means that there is indeed a hidden variable theory in this world, but things are contrary to expectations. Originally, Bell wanted to use this to prove the incompleteness of quantum mechanics, but he unexpectedly consolidated the correctness of quantum mechanics.
This point is somewhat similar to the story of Poisson's theory of fluctuation in opposition to the theory of light fluctuation, which used this theory to calculate the "Poisson's bright spots".
Summary
Therefore, in general, although the award-winning experiments and techniques have been implemented for many years, the promulgation of this Nobel Prize in Physics is not only an affirmation of these physicists, but also a higher communication perspective, allowing the public to hear about quantum mechanics.
The first quantum entanglement photo
And there is Einstein, the founder of the theory of relativity and the veteran of quantum theory , which also denied some of his ideas and beliefs about the quantum world. At present, it seems that he is indeed wrong.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-