Scientists verify the “parallel time and space“: Is the science fiction plot really going to enter the real world? |The Beijing News Column

2020-08-01 17:24:16 0 Comment 2013 views

Movie "Arrival" Stills | Sun Zhengfan In science fiction and film and television culture, netizens have a very vivid comment: logic is unreasonable, p

Scientists verify the “parallel time and space“: Is the science fiction plot really going to enter the real world? |The Beijing News Column

A free neutron has a one-percent chance of crossing the mirror universe? The scientific community does not reject even the most bizarre conjectures, but only after passing tests can they become scientific theories. In fact, scientists are not optimistic.

Scientists verify the “parallel time and space“: Is the science fiction plot really going to enter the real world? |The Beijing News Column

Film "Arrival" Stills


In sci-fi novels and film and television culture, netizens have a very vivid and vivid expression: logic is unreasonable, parallel time and space; can not be compiled, quantum war clothes. Just like Thanos can destroy the world and reload the process with a snap of his fingers, parallel time and space, quantum uncertainty, these elusive sci-fi settings, give the protagonist of sci-fi stories "superpowers."

But do you know? Scientists who are usually rigorous and meticulous, when they are forced by scientific problems to be helpless, will also sacrifice the less reliable setting of "parallel space-time", hoping to explain the problems that have plagued scientists for decades in cutting-edge science. Solve the mystery.

Recently, according to "New Scientist" magazine (New Scientist), the physicist Leah Leah at Oak Ridge National Laboratory in Tennessee (Oak Ridge was the birthplace of the first atomic bomb in human history) BruzaLeah Broussard and her team tried to detect the existence of mirrored parallel universes in the laboratory to solve a problem that has existed in the field of neutron decay research for 40 years.

Using science fiction settings to solve scientific problems, what is going on?

What is a mirrored parallel universe

In fact, the so-called sci-fi setting is originally used for scientific discovery. For example, the mirror parallel universe actually involves two basic quantum physics concepts, parity (mirror symmetry), and the "parallel space-time" extended by probability interpretation.

In our lives, we can see many simple mirror images, that is, symmetrical graphics. In the field of classical physics, the left and right directions are exactly the same. The world in the mirror and the world outside the mirror can exist perfectly. But in quantum forceIn the academic field, this symmetry was broken by the "parity non-conservation" discovered by Yang Zhenning and Li Zhengdao, which uncovered the famous "θ-τ mystery" at the time, that is, in the weak work Strong (Four basic worksStrong One) Parity is not conserved in the nuclear reaction process involved.

Not only that, Yang and Li also designed experiments to prove the effect caused by this non-conservation. Chinese scientist Wu JianxiongShi quickly made one of the experiments, which proved that Yang and Li's theories were correct, overturned the long-term default "parity conservation" and shocked the physics community. ——In quantum mechanics, the world inside the mirror is actually different from the world outside the mirror.

So, Yang Zhenning and Li Zhengdao published a paper in October 1956, and Wu Jianxiong then gave experimental verification, The Nobel Prize Committee immediately put The Nobel Prize was awarded to Yang Zhenning, who was only 35 years old, and Li Zhengdao, who was 31 years old.

As for the parallel universe, science fiction fans are already familiar with it. In Quantum In the interpretation of probability waves, the poor "Schrödinger’s cat" in the box was both dead and alive before being observed. It was a superposition of two states. After being observed, understand it to change There is only one state of becoming, either dead or alive.

So, where did the other state go? There is an explanation that the other state still exists, and it’s our universe. In parallel time and space, the cat becomes another state. This change and interpretation of the quantum world is completely inconsistent with our life experience and classical physics. But the law of the quantum world is exactly this, for this This "parallel universe" interpretation cannot be verified by those who agree, nor can it be falsified by opponents.Then... let him go. Look, the science fiction assumptions we are familiar with come from the original whims of scientists.

Scientists verify the “parallel time and space“: Is the science fiction plot really going to enter the real world? |The Beijing News Column

Film "Interstellar Interstellar" stills

40 years of neutron decay problem, forcing the "mirror parallel universe experiment"

Report The protagonist Leah Broussard (Leah Broussard) studies neutron physics at the famous Oak Ridge National Laboratory. Neutrons are uncharged particles that exist in almost all atomic nuclei. It has a peculiar property, in the nucleus it has propertiesThe quality is very stable and can exist for a long time, although sometimes it is not honest, it will decay, from neutron to proton, throw out an electron and a neutrino by the way (let Yang and Li get the first one for the Chinese Nobel Prize is such a nuclear decay).

But if the neutrons are free, they immediately enter the senescence phase, decay, and lose half of them every 15 minutes (this time is called the "half-life").

The problem lies in the accurate measurement of free neutrons "about 15 minutes". Neutron physicists have two ways to measure it. One way is to isolate them in a "bottle trap" and letIt stays quietly, decays freely, and counts the remaining quantities after a certain period of time; another method is to take a bunch of running neutrons from the nuclear reactor, set a card on the running route, and count the neutrons after they decay. The number of protons produced. But the half-life results obtained by these two methods are always the same-the former is 14 minutes and 39 seconds, and the latter is 14 minutes and 48 seconds. In other words, in about 900 seconds, the difference between the two results is 9 seconds.

Regardless of whether it is a scientist from the birthplace of the atomic bomb or a scientist from other countries, the two types of experiments have been repeated countless times, and there is always a difference-it is not a careless scientist who made a mistake, or a problem with the experimental instrument . For 40 years, neutron physicists have racked their brains to figure out what went wrong that caused this inconsistency—both Newton and Einstein have promised us, whether it’s quiet, Or running particles, theirThe rules should be the same.

Like in a sci-fi story, facing the "plot" in our world that can't be completed according to rigorous scientific logic, Leah Brusa of Oak Ridge National Laboratory Er and his colleagues were forced to sacrifice a magic weapon commonly used by science fiction writers: parallel time and space, and mirror images.

The explanation is that there may be mirror parallel universes. 1% of the neutrons in the running neutron beam have the ability to travel to the mirror parallel universe. They have also decayed, but they are not In our universe, those decayed protons are lost, and the observation results "appear" to have a longer half-life. (This conjecture was mentioned in a 2012 paper.)

The experiment has not yet started, and the results are not optimistic

How to prove "in The child crossed to the mirror parallelWhat about the “universe”? Brussard’s experimental design looks a bit "whimsical": what she envisioned is to allow neutrons to travel back through. To this end, a thick wall must be set up, which is the neutron in our universe It can’t be penetrated anyway.

According to the hypothesis of the "mirror parallel universe", in the running neutron beam, some neutrons do not need to be trapped in the wall, while other neutrons hit the wall head-on and fall. When they were in the wall, they went to another universe to stroll around, which is equivalent to bypassing the wall, then crossing back, and appearing behind the wall.

So, the idea of ​​the scientists is on the wall A detection device is set up later to catch these "cunning" neutrons that have successfully overturned the wall using the mirrored parallel universe. In this way, two experiments to measure the half-life of neutrons can obtain consistent results.

But for now In other words, it’s too early to make any evaluations, because although the experimental idea is completed, when will it start?The exhibition still needs to wait for the analysis of the results of another preliminary experiment. The scientist who presided over the experiment and was still analyzing the data said: "Although the possibility of getting any results is very small, this is a simple and inexpensive experiment. If a physics revolution may produce good results , Then we must try."

Listen, there is a "small chance" of success, so why do these experiments? Because "simple and not expensive". In other words, because neutron physicists have been exploring this problem for 40 years, they found desperately that it seems that there is no answer in our universe. Therefore, those ideas with science fiction have entered. The vision of scientists. And because the cost is really cheap, the idea of ​​such a big brain may be put into practice.

In other words, it may be a great experiment to change the course of science, but the probability is too small, even moreIt may be an anecdote that we will remember only after a few years of jokes on scientists.

How to understand scientists’ testing of "science fiction settings"

In his popular science book "The Evolution of Physics", Einstein once put scientific research Compare it to a detective solving a case. However, unlike ordinary detective novels, it is impossible for scientists to turn to the end to see the final answer. In the process of solving the case, no one knows in advance what the final answer will be and when it will appear. Even more embarrassing is that scientists like Hawking still believe that we may not have the final answer.

However, in a scientific problem that everyone is helpless, scientists will not reject any possibility, even if it is an explanation like "mirror parallel time and space" that even designers may not really believe. However, scientists will not stop atIn fantasy, if you want to admit or deny (confirm or falsify), you must find experimental evidence that can explain the problem.

In fact, this matter can also help us understand the relationship between theoretical explanation and experimental verification in science. In modern science, scientific experiments are to test (confirm or falsify) certain scientific theoretical conjectures. In other words, before any scientific experiment is carried out, there must be sufficient evidence for it to be valuable. The hypothesis of mirroring parallel space-time like this is not very reliable in theory, but this experimental design has an advantage, that is, its cost is very low, and the technology is readily available, so this experiment can be smooth. To enter the implementation stage.

Another inspiration is that the conclusions of scientific experiment design must be open, and any scientist must accept any possible results given by the scientific experiment: verification or falsification. If this experiment really detects neutron signals behind the "impossible wall", then physicists will be surprised. There will be more experiments of the same kind to test, and a large number of theoretical scholars will also The space-time hypothesis was enthusiastically discussed, setting off a new revolution in physics.

Of course, there is another possibility, that even the designer thinks, that this experiment did not detect any neutron signal. In other words, at least this experiment will reduce the possibility of the existence of the hypothesis of "mirror parallel space-time"-future science fiction writers will be more cautious when using this concept, right?

Of course, this double possibility is precisely the most attractive part of scientific experiments. For many world-famous large scientific devices—for example, the Large Hadron Collider at the European Nuclear Center, some scientific reviews wrote that if it can make some scientific discoveries according to theoretical expectations, we can be happy.Phew, this is a great victory for modern physics.

However, deep down in the hearts of scientists, they may even expect them to give different results. This will make scientists more excited, because it means that experiments have pointed out the problems and shortcomings of the current scientific physics model, forcing physicists to go beyond it and revolutionize modern physics on a deeper level.

But, where is the answer in the future? Even the most cutting-edge physicists don’t know, so everyone welcomes even the most amazing ideas. Of course, "who advocates who provides evidence", the person who proposed the idea must, like the scientist, propose the best and lower-cost test plan. We must also admit that we still do not know where the final answer is. It is also possible that after many years, people will look back at history and find that even the wildest imagination of scientists today is too conservative.

□Sun Zhengfan(Doctor of Astrophysics)

Editor: Li Bingbing Proofreading: Li Lijun

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