Reborn and become a Great Scientist

Chapter 155 103 Gamma Ray Microscopy

When he received Einstein's letter, Chen Muwu was working with three of his students in the laboratory, imitating the vacuum pump purchased from General Electric in the United States.

After Rutherford's birthday, Chen Muwu, who had intensively proposed a lot of physical theories some time ago, finally shifted his focus from theory to experiment, and started to develop electron microscopes.

Although there is a patent certificate in hand, the patent only contains a few principles. After the actual hands-on operation, Chen Muwu finally realized how difficult it is to create such a big guy in the laboratory.

The electron source and electron lens are trivial matters. The key is to make an electron microscope with a magnification much higher than that of an optical microscope, and the requirements for a vacuum environment are also very high.

Unlike a glass tube with a length of less than [-] centimeters, an electron diffraction experiment can be completed.

The length of the vacuum cavity in the electron microscope must be at least two meters.

If you only rely on the previous General Electric vacuum pump to extract the vacuum, the efficiency is too low.

Therefore, the first step in making an electron microscope is to try to see if the speed of the vacuum can be increased, and then slightly accelerated.

Although he had always resisted letting Oppenheimer get in touch with specific experiments, but because of the lack of manpower, he decided to let Oppenheimer, Zhao Zhongyao and Shi Ruwei come to the laboratory. help.

Zhao Zhongyao and Shi Ruwei finally passed the entrance examination without any surprises, entered Trinity College, Cambridge University, and became alumni with Chen Muwu.

His previous relationship with Ramsey, the son of the head of the Magdalen Academy in the Apostolic Society, was useless after all.

How to reduce the vacuum in the vacuum cavity of the electron microscope is one problem, and how to make the electron wave finally image after several times of amplification is another problem.

The electron microscope used by Chen Muwu in the laboratory in his previous life was an image formed by connecting the CCD photosensitive element to the computer, but obviously in this era, it is very unrealistic to create these two things.

So what Chen Muwu thought was, either use photographic film to form images like the electron diffraction experiment.

Or simply use a fluorescent screen, allowing the electronic signal to interact with the fluorescent material on the screen for final imaging.

It's just that no matter which of these two methods you choose, it is not very convenient and efficient, and it can only be regarded as barely used.

Chen Muwu felt that he had taken it for granted at the beginning, thinking that since he had mastered the principle and had a lot of funds, it only took a month or two to develop the electron microscope.

But the various difficulties before everyone directly shattered the thoughts in his brain.

Chen Muwu felt that it would take at least a year and a half to make this electron microscope.

Although the stagnation of this progress made Chen Muwu a little depressed, Oppenheimer always maintained a state of high spirits.

He even turned his back on his teacher: "Mr. Chen, I don't think you should feel discouraged because of such a small setback.

"As far as I know, Mr. Edison, the 'King of Invention', made more than a thousand attempts, tested countless materials and designs before finally inventing the light bulb, and finally succeeded in making the first bulb using carbon filaments. Bulb……"

Why can I still hear such poisonous chicken soup for the soul after traveling to 100 years ago?

Chen Muwu was a little dumbfounded. Oppenheimer should not stay in the laboratory, but should be given to Penguin Press, and let him write chicken soup for the soul for that magazine, so as to nourish the indifference of people in this era. And a dry heart.

However, Oppenheimer's performance in the laboratory surprised Chen Muwu. Although he was not as hard-working as the two Chinese compatriots, he also had a strong execution ability, and he did not cause damage in the laboratory. What's wrong with it.

It may be that Blackett did not read Oppenheimer's instruction manual at the beginning, and sent him to do a lot of simple and repetitive labor instead of creative experiments, which led to his dissatisfaction.

Einstein's letter was sent by Kapitsa from Trinity College to Chen Muwu to the Cavendish Laboratory.

"Chen, I have another letter from you!"

"Thank you Peter, why are you so diligent today?"

In Chen Muwu's memory, this should be the first letter Kapitsa brought him, and it was Blackett's work before that.

"Actually, I don't want to bring it to you. After all, you receive so many letters every time. It's just that I just saw that the sender of this letter is Dr. Einstein. I was afraid that it would delay your affairs, so I gave it to you." Bring it here. Take a look, what is written in this letter?"

The arrival of this letter, especially Kapica's mention of Einstein's name, finally temporarily boosted the somewhat low morale in the laboratory.

Whether it is Zhao Zhongyao and Shi Ruwei from China, or Oppenheimer from the United States, everyone knows the name of Einstein, but no one knows the relationship between Chen Muwu and Einstein.

Although Oppenheimer was studying the vacuum pump, he would glance at Chen Muwu from time to time, curious about what the most famous scientist in the world would write to his teacher.

"Dear Chen:
"I haven't written to you for a long time, and I haven't heard from you.

"First of all, congratulations on your achievement of four gold medals in the Paris Olympics that just passed.

"Now I am a little fortunate that I met you in Shanghai and discovered a talent like you for the physics community.

"I thought, if we hadn't met at that lecture, maybe physics would have lost a genius, and your country would have gained a dedicated swimmer."

After reading this, Chen Muwu felt that Einstein was a little pretentious.

Although he still respects and appreciates Einstein very much in his heart, if he said that without Einstein, Chen Muwu would not be where he is today, and he does not quite agree with it.

Even without Einstein's visit to China to give lectures, Chen Muwu still had other ways to participate in the revolution in physics in the 20s.

He can go north to Tsinghua University to obtain the indemnity for Gengzi's study in the United States in [-], and then, together with Xie Wanying, Liang Shiqiu, Wu Wenzao, and Sun Liren, boarded the steamer York Sun in the Qihai Sea and sailed to the United States on the other side of the Pacific Ocean. Study in the United States.

If he didn't want to go to that free country full of discrimination, it would not be a problem for Chen Muwu to study in Germany only by relying on the property of the Chen family.

As long as he holds ocean or U.S. dollars tightly in his hands and does not exchange them for Deutsche marks unless he has to, he can spend a good year in Germany comfortably in 1923.

Chen Muwu didn't want to waste too much time on Einstein's compliment, so he continued to read the letter in his hand.

"I have read several papers on the laws of motion in the microscopic world that you published this summer in Annals of Physics and the British journal Nature, and to be honest, these few papers of yours confuse me.

"In your paper "On Quantum Mechanics" you point out that you use the same principles of Mach's philosophy in the matter of electron orbits as I did in formulating the theory of relativity.

"But what I want to say is that there are still some differences between the two. I use the principle of observability to deny some artificially added concepts to explain real phenomena, such as ether, absolute time, absolute space and simultaneity.

"But in your paper, you mentioned that because you can't observe it, you think that electron orbits don't exist, which is a somewhat radical point of view. I really find it hard to agree.

"Mach's skeptical philosophical view could not create anything alive, perhaps only exterminate harmful insects.

"Even his own viewpoint that 'atoms do not exist because atoms cannot be observed' has been confirmed by the experiments of Sir Thomson and Sir Rusev in recent years, which is fundamentally a fallacy.

"What I must advise you is that there is an objective reality whether we can observe it or not. The belief in an external world independent of human observation is the basis of all science.

"As for the explanation of the probability wave you put forward to explain what the wave function is, I think it is even more nonsense.

"The ultimate goal of physics is to discover strictly definite causal laws. It is impossible for electrons to exist here and there, and to be distributed throughout the entire space at the same time as you stated."

Einstein's ability to write such words in the letter was completely expected by Chen Muwu.

His philosophical views made him no longer as radical as he was when he was young, and gradually changed from a physics desperate to an apologist.

"Frankly, I am not a staunch atheist, and while I do not believe in a personal God who governs everything, I have always believed that the undiscovered elegant laws governing the universe reflect a divine the design of.

"When I'm in doubt about whether a theory is true, I often ask myself, if I were God, would I design the world in this way?
"I suppose a good God would not create wonderful and subtle rules to determine most things that happen in the universe, leaving a few things entirely to chance and probability.

"If he did, I don't think we'd have to bother looking for laws at all.

"The quantum mechanics you came up with are amazing, but there's always a voice in my head telling me that's not real. You say a lot in theory, but it doesn't bring us any closer" The old man's secret.

"Anyway, I am sure there is no mahjong in heaven, nor is He playing dice.

"Albert Einstein in Berlin"

After much anticipation, Chen Muwu finally found this sentence at the end of the letter.

The famous quote that would have appeared in the letter to Born was now cut into his own hands by him.

Chen Muwu planned in his heart that he must keep this letter well and donate it to a museum later, or put it in a museum named after himself.

Wanting to thoroughly convince Einstein in quantum mechanics is something that many physicists have failed to accomplish after decades.

If you try to convince him with various examples, you will never get approval, but a stronger counterattack from Einstein.

So Chen Muwu didn't intend to do this kind of useless work to bump into the south wall of this building called Einstein.

Since the old German is so opposed to probability and chance, let his objection be louder.

The electron microscope that was being developed in the laboratory at the moment brought him inspiration, so Chen Muwu put the typing paper into the typewriter and typed a reply to Einstein.

"Mr. Einstein, hello!

"Your letter of the past few days has been received, thank you for your congratulations, and thank you for your interest in my progress in physics.

"Let me tell you about the work I'm currently working on..."

Anyway, the paper and the ink ribbon are not drawn on his own money, so Chen Muwu brazenly typed a lot of nonsense, starting with his proof that electrons are a kind of wave, and then talking about his plan to use electron waves to compare with the wavelength of visible light waves. Shorter this feature, to create a microscope with higher resolution.

After talking about the electron microscope, this letter finally got to the point.

"Doctor, the reason why I choose electrons instead of electromagnetic waves with shorter wavelengths, which is what we call gamma rays, to develop a microscope with higher resolution is because the materials of the current optical components are far from meeting the requirements. During the refraction process, the gamma rays will produce a very strong scattering phenomenon, and finally cannot be focused, thus failing to meet the microscopic requirements.

"But if one day, we humans can really manufacture high-resolution gamma-ray microscopes, maybe at that time, we can observe many things that cannot be observed under visible light microscopes, for example, the position of an electron.

"The shorter the wavelength of the gamma rays, the more precisely the position of the electron can be measured.

"However, at this time, we will face a more serious problem. The wavelength of gamma rays is inversely proportional to their energy. The shorter the wavelength, the higher the energy. High-energy gamma rays will inevitably interact with electrons called ' Chen scattering' collision, which will cause the electron to suddenly receive a large momentum,

"That is to say, the exact velocity of an electron cannot be obtained while accurately determining the position of the electron. At this time, the orbit of the electron is still uncertain."

"On the contrary, if you want to avoid electrons being perturbed by large momentum as much as possible, you need to use photons with the lowest possible energy to detect electrons, but in this way, there is no way to accurately measure the position of electrons, and it is also impossible to determine the orbit of electrons.

"Of course, whether humans can create a gamma-ray microscope is still unknown, and the experiment mentioned above is just a thought experiment that exists in the brain.

"But I think this does not prevent us from making a qualitative and semi-quantitative error estimate for this experiment.

"According to the Abbe's formula that can obtain the resolving power of the microscope, assuming that the wavelength of the incident light is λ, and the opening angle of the electron to the radius of the lens system is θ, then the observation error in the position of the electron is x~λ/sinθ.

"According to the law of conservation of momentum in Chen's scattering, and assuming that after the scattering is completed, the photon's momentum p=h/λ remains unchanged and only changes its direction, then the momentum error Δp~h/λsinθ that the photon brings to the electron.

"Multiplying the position error and the momentum error gives us ΔxΔp~h.

"That is to say, it is impossible to accurately measure the electron's momentum while accurately measuring the position of the electron. I will tentatively name this inaccurate relationship as the uncertainty principle.

"If electrons are replaced with other microscopic particles, I think this uncertainty principle will still exist.

"Time is limited, so I can only briefly introduce my thoughts to you in this letter with such a thought experiment.

"Another point to make is that, as a Chinese, I am not a believer in God.

"However, here, I would like to tell you another sentence. More than 2000 years ago, there was a great philosopher in China named Confucius. He once said, 'A gentleman has three fears', among which the first one is Fear of destiny.

"Whether it's God or destiny, I don't think we should use our mortal bodies to tell God what he should do."

"As for the rigorous derivation process of this uncertainty principle, I will organize it into a paper and publish it in "Annual Review of Physics" or "Nature" journals in the future, please pay attention.

"As for whether this principle is correct or not, I ask for your advice.

"Finally, I wish you success in your work, good health, and a lot of laughter.

"Your student, Chen Muwu."

As humble as Chen Muwu wrote this letter, the content he mentioned in the letter is as explosive as it is.

The uncertainty principle appeared in this world for the first time in this reply letter.

At the time, Professor Wien, who was in charge of the doctoral graduation experimental examination at the University of Göttingen, almost failed to allow this conceited German to obtain a doctorate because Heisenberg could not answer how to calculate the resolution of the optical system.

But Heisenberg was also a blessing in disguise. He firmly remembered how to calculate the resolution, and one day he had a burst of inspiration. From this formula, he derived the principle of uncertainty.

Now that he threw out this big weapon, Chen Muwu had no choice but to hurry up and write a paper to verify the correctness of this principle theoretically.

This is because the thought experiment of Heisenberg he threw out in his reply to Einstein, of course there is nothing wrong with bluffing people in the letter, but as long as you think about it carefully, you can know that it is actually not rigorous, and you still face many problems. difficulty.

First of all, in the thought experiment, it is assumed that the electron has a definite position and momentum before measurement, which itself violates the uncertainty principle, and there is no way to verify it by experiment.

The second is the error x calculation method used in this experiment, which is actually a statistical average result.

And this statistical average, at least here, is not applicable.

Although Chen Muwu has advanced knowledge reserves, Einstein, known as having the most intelligent brain in human history, is of course not a vegetarian.

If he is left with this kind of handle in the letter and does not resolve it finally, then these loopholes will become a powerful weapon for Einstein when he fights back.

So as soon as he typed the last punctuation mark on the letter on the keyboard of the typewriter, Chen Muwu began to think about how to write this thesis well.

He took the last sheet of printing paper out of the typewriter, read the letter from beginning to end, and after confirming that there were no spelling, grammatical and logical errors in it, he took out an envelope from his desk and folded the letter paper Put it in.

After sealing the envelope, Chen Muwu put two one-penny and one half-penny stamps on it, intending to find a mailbox after get off work and post the letter.

When he looked up, he found that Kapitsa was still sitting on the sofa in his laboratory, showing no intention of leaving.

"Is there anything else you want, Peter?"

"Actually, it's not a big deal, but it's the first time I see the Chinese compatriots you keep talking about, so I want you to introduce them to me and say hello to them by the way."

This is of course no problem, Chen Muwu immediately introduced each other to the three.

But during the introduction, he found that something was wrong again. It took him at least half an hour to write his reply letter, and he, Kapitsa, stayed here all the time. Obviously, he didn't want to make an introduction as simple as that.

"Peter, if you have anything else to do, just say it!"

Kapitsa, who was punctured, was not at all shy: "I also want to ask Mr. Zhao and Mr. Shi, can they cook Chinese food? Since George left Cambridge University, I haven't tasted oriental food for a long time .”

"Go, go! They came all the way to England, not to cook for you! If you really want to eat, I'll take you to London when I get a chance."

Chen Muwu kicked Kapiza out with a smile, and he knew he had no good intentions.

It's okay for Ye Gongchao to cook, but these two can't cook for you!

Seeing that his teacher had not only finished reading Einstein's letter, but had even written a reply to him, Oppenheimer couldn't help but come over.

After getting along for more than half a month, Oppenheimer has learned that his teacher is actually not as serious as when he first met, but a very elegant and easy-going person.

That's why he can boldly ask now: "Mr. Chen, are you also familiar with Professor Einstein?

"Because I am very curious about Professor Einstein, I have been quietly observing you just now, and found that your expression is sometimes relaxed and sometimes frowning. I don't know what happened?"

Zhao Zhongyao and Shi Ruwei on the other side of the laboratory also quietly pricked up their ears.

"What happened? Of course he didn't understand the last few papers I wrote, so he wrote to me to ask some questions.

"Although I have already given the answer in the reply letter, it is estimated that he who is stubborn will probably not agree with my point of view.

"Robert, in comparison, you as a student make me feel more at ease."

Relying on this way of joking, Chen Muwu spoke the truth.

Oppenheimer was smiling on the surface, but what he thought in his heart was that his teacher was indeed elegant and easy-going, but the only shortcoming was that sometimes he would brag too much!

But he actually praised me just now that I am better than Einstein. It seems that I really did not follow the wrong mentor, and I must work hard under his hands.

(End of this chapter)