When he received Einstein's letter, Chen Muwu was working in the lab with three of his students, replicating the vacuum pump he had purchased from General Electric.

After Rutherford's birthday, Chen Muwu, who had intensively put forward a lot of physical theories some time ago, finally put the focus of his work back from theory to experiments, and began to develop electron microscopes.

Although he has a patent certificate in hand, but the patent is only written with a few words of principle, after the actual operation, Chen Muwu finally knows how difficult it is to get such a big guy out of the laboratory.

Both the electron source and the electron lens are trivial matters, and 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 glass tubes with a length of less than 50 centimeters, which can complete an electron diffraction experiment.

The length of the vacuum chamber in the electron microscope should also be at least two meters.

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

Therefore, the first step in making an electron microscope is to try to see if you can increase the speed of the vacuum level, and then speed it up a little.

Although he had always resisted letting Oppenheimer get in touch with specific experiments, because of the lack of manpower, he became a live horse doctor and asked Oppenheimer, Zhao Zhongyao and Shi Ruwei to come to the laboratory to help.

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

The relationship he had with Ramsey, the son of the head of the Magdalen Academy in the Apostolic Society, was still useless after all.

How to reduce the vacuum in the vacuum chamber of the electron microscope is a problem, and how to make the electron waves finally image after several amplifications is another problem.

In his previous life, the electron microscope used by Chen Muwu in the laboratory was made after connecting to the computer through a CCD sensor, but obviously in this era, it is very unrealistic to want to make these two things.

So what Chen Muwu thought was that he would either use a photographic film to image as in an electron diffraction experiment.

Or simply use a phosphor screen to allow the electrical 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's not very convenient and efficient, and you can only barely use it.

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 money, it only took one or two months to develop the electron microscope.

But the difficulties in front of everyone now 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 this progress has stalled, Chen Muwu has some low pressure, but Oppenheimer has always maintained a state of high spirits.

He even gave his teacher a beating in turn: "Teacher Chen, I don't think you should be discouraged because of such a small setback.

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

Why have they all traveled a hundred years ago, but they can still hear such poisonous chicken soup for the soul?

Chen Muwu couldn't laugh or cry, Oppenheimer shouldn't stay in the laboratory, but should send it to Penguin Press, and let him write all kinds of chicken soup for the soul for that magazine, so as to nourish the cold and dry hearts of people in this era.

However, Oppenheimer's performance in the laboratory surprised Chen Muwu a little, although he was not as hard-working as the two Chinese compatriots, but he also had a very strong execution, and he did not cause damage in the laboratory and make any moths.

It may be that Blackett did not read Oppenheimer's instruction manual in the first place, and sent him to do a lot of simple and repetitive work rather than creative experiments, which led to his dissatisfaction.

Einstein's letter was brought to Cavendish's laboratory by Kapitsa from Trinity College to Chen Muwu.

"Chen, there is your letter again!"

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

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

"Actually, I don't want to bring it to you, after all, you get so many letters every time. It's just that I happened to see that the sender of this letter was Dr. Einstein, and I was afraid that it would delay your business, so I brought it to you. Look at it, what's in this letter? ”

The arrival of this letter, especially the mention of Einstein by Kapitsa, finally gave a temporary boost to the somewhat depressed morale in the laboratory.

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

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

"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 four gold medals at the Paris Olympics.

"Now I am a little glad that I met you in Shanghai and discovered such a talent as you for the physics community.

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

Reading this, Chen Muwu felt that Einstein was a little self-inflicted.

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

Even without Einstein's visit to China to give lectures, Chen Muwu still had other ways to participate in the transformation of physics in the twenties of the twentieth century.

He could have gone north to Tsinghua School to obtain the 1923 Gengzi indemnity for studying in the United States, and then, together with Xie Wanying, Liang Shiqiu, Wu Wenzao, Sun Liren, and others, boarded the Yorkson steamship in the sea and sailed to the United States on the other side of the Pacific Ocean to study.

If you don't want to go to that free country full of discrimination, just relying on the Chen family's property, it will not be a problem for Chen Muwu to study in Germany.

As long as he held the ocean or the dollar tightly in his hand, and did not exchange the Deutsche mark until the last resort, then he could have a good 1923 in Germany.

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

"I've read several of your papers on the laws of motion in the microscopic world this summer, published in the Annals of Physics and the British journal Nature, and to be honest, your papers have puzzled me.

"In this paper on quantum mechanics, you point out that you use the same Mach philosophical principles in the question of electron orbitals as I did when I proposed the theory of relativity.

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

"But in your paper, you mentioned that because you can't observe, you don't think there are electron orbitals, which is a bit radical, and I really can't agree with it.

"Mach's philosophy of skepticism makes it impossible to create anything alive, perhaps only to destroy harmful insects.

"Even his own argument that because atoms are not observable, they do not exist, has been confirmed by the experiments of Sir Thomson and Sir Rutherf in recent years, which is a fallacy at all.

"One thing I must advise you is that there is an objective reality, whether we can observe it or not. Belief in an outer world, independent of human observation, is the foundation of all science.

"As for the explanation of probability waves that you put forward in order to explain what the wave function is, I think this is more nonsense.

"The ultimate goal of physics is to discover the laws of cause and effect that are strictly determined, and that electrons cannot exist here and there, distributed throughout space at the same time, as you suggest."

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

His philosophical views made him no longer as radical as he was when he was younger, and gradually transformed from a physicist to an apologetic.

"Frankly, I'm not a staunch atheist, and while I don't believe in a personified God who governs everything on earth, I've always believed that the undiscovered, graceful laws that govern the universe reflect a divine design.

"When I'm not sure if a theory is correct, I often ask myself, if I were God, would I have designed the world this way?

"I don't think a good God would have created wonderful and subtle rules to determine most of what happens in the universe, leaving a few things entirely to chance and probability.

"If he did, I don't think we would have to bother looking for the so-called laws at all.

"The quantum mechanics you came up with are amazing, but there's always a voice in my head telling me that it's not the real thing. You say a lot in your theories, but you don't have the slightest hint of bringing us closer to the 'old man'.

"In any case, I'm sure there is no mahjong in heaven and He's not rolling dice.

"Albert Einstein in Berlin"

After a long period of anticipation, Chen Muwu finally found this sentence at the end of the letter.

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

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

Convincing Einstein completely in quantum mechanics is something that many physicists have not been able to accomplish for decades.

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

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

Since this old German man is so opposed to probability and chance, it is better to make his opposition louder.

The electron microscope he was developing in the laboratory at the moment gave him inspiration, so Chen Muwu loaded the typewriting paper into the typewriter and typed Einstein in reply.

"Hello, Mr. Einstein!

"Thank you for your congratulations and for your interest in the progress I have made in physics.

"Below I will tell you about what I am currently working on......"

Anyway, the paper and ink strips are not his own money, so Chen Muwu unscrupulously knocked down a lot of nonsense, starting with his proof that electrons are a kind of waves, and then talking about his intention to use the shorter wavelength of electron waves than visible light waves to build a microscope with higher resolution.

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

"Doctor, the reason why I chose electrons instead of electromagnetic waves with shorter wavelengths, which is what we call gamma rays, to develop a higher resolution microscope is because the material of the current optical components is far from meeting the requirements, which will cause the gamma rays to produce a very strong scattering phenomenon in the refraction process, and finally cannot be focused, so as to fail to meet the requirements of microscopy.

"But if one day, we humans can actually build a high-resolution gamma-ray microscope, maybe then we will be able to observe many things that cannot be observed under a visible light microscope, such as the position of an electron.

"The shorter the wavelength of the gamma rays, the more accurate the measured position of the electrons.

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

"That is, it is not possible to accurately determine the position of an electron and at the same time obtain the exact velocity of an electron, and the orbit of the electron is still uncertain."

"Conversely, if you want to avoid large momentum disturbances to electrons, you need to use photons with the lowest possible energy to detect electrons, but in this way, it is impossible to accurately measure the position of the electrons, and the orbits of the electrons cannot be determined.

Of course, it is still unknown whether humans can make a microscope with gamma rays, and the above experiment is just a thought experiment that exists in the brain.

"But I don't think that prevents us from making a qualitative semi-quantitative error estimate for this experiment.

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

According to Chen's law of conservation of momentum in scattering, and assuming that after the scattering is completed, the momentum of the photon p=h/λ does not change but changes direction, then the momentum error caused by the photon to the electron is Δp~h/λsinθ.

"Multiply the position error and the momentum error to get ΔxΔp~h.

This means that it is not possible to accurately measure the position of an electron and at the same time the momentum of an electron. I will call this uncertainty relationship the uncertainty principle.

"If you replace the electron with another microscopic particle, I think the 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 note is that as a Chinese, I am not a believer in God.

"However, here, I would like to tell you another sentence, more than 2,000 years ago, there was a great philosopher named Confucius in China, who once said, 'A gentleman has three fears', and the first of them is the fear of the destiny of heaven.

"Whether it's God or destiny, I don't think we should tell God what he should do in a mortal body."

"As for the rigorous derivation process of this uncertainty principle, I will compile it into a paper and publish it in the Annals of Physics or the journal Nature in the future, so please keep an eye out for it.

As for whether this principle is correct or not, please advise me a lot.

"Finally, I wish you all the best in your work, good health, and a smile on your face.

"Your student, Chen Muwu."

How humble Chen Muwu's letter is, how powerful the content he mentions in the letter is.

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

Professor Wien, who was in charge of the doctoral examination at the University of Göttingen, almost failed to get the vaunted German to get his doctorate because Heisenberg could not answer how to calculate the resolution of an optical system.

But Heisenberg was a blessing in disguise, remembering how to calculate resolution, and one day he had an inspiration to derive the uncertainty principle from this formula.

Since he threw out this big killing weapon, Chen Muwu had to hurry up and write a paper to verify the correctness of this principle theoretically.

This is because of Heisenberg's thought experiment that he threw out in his reply to Einstein, and there is certainly nothing wrong with bluffing people in the letter, but as long as you think about it carefully, you can see that it is actually not rigorous, and it still faces many difficulties.

First of all, in the thought experiment, it is assumed that the electron has a definite position and momentum before it is measured, which in itself violates the uncertainty principle and cannot be verified experimentally.

The second is that the error x calculation method used in this experiment is actually a statistical averaging result.

And this statistical average, at least here, does not apply.

Although Chen Muwu has advanced knowledge reserves, Einstein, who is known as having the smartest brain in human history, is certainly not a vegetarian.

If he is left with such a handle in the letter, and does not finally solve it, then these loopholes will become a powerful weapon for Einstein to fight 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 paper well.

He took the last piece of printer paper off the typewriter and read through the letter from beginning to end, making sure that there were no spelling, grammar, or logical errors in the contents, before he pulled out an envelope from his desk, folded the letter, and put it inside.

After sealing the envelope, Chen Muwu put two one-penny and one-half-pence stamps on it, planning to find a mailbox after work and send the letter.

When he looked up, he saw that Kapitsa was still sitting on the couch in his lab, with no intention of leaving.

"Is there anything else you need, Peter?"

"Actually, it's not a big deal, it's just that it's the first time I've seen the Chinese compatriots you've been talking about, so I want you to introduce me and say hello to them by the way."

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

But when he was introduced, he found that the problem was not quite right, and his reply letter was written for at least half an hour, and he Kapitsa had been staying here, obviously not trying to introduce him to him.

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

Kapitsa, who was punctured in his heart, was not shy at all: "I also want to ask Mr. Zhao and Mr. Shi, can they cook Chinese cuisine?" It's been a long time since George left Cambridge that I haven't tasted the Orient. ”

"Go, go, go! They didn't come all the way to England to cook for you! If you really want to eat, I'll take you to London sometime. ”

Chen Muwu even laughed and drove Kapitsa out, knowing that he didn't have any good intentions.

Ye Gongchao doesn't have to cook, but these two must not cook for you!

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

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

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

"Because I'm curious about Professor Einstein, I've been quietly observing you just now, and I noticed that your expression is sometimes relaxed, sometimes frowning, and 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 had written, so he wrote to me to ask some questions.

Although I have already given the answer in my reply, I guess he will most of the stubborn ones not agree with my point of view.

"Robert, in comparison, it's you, the student, who is more worry-free."

Chen Muwu relied on this joking way to tell the truth.

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

However, he just praised me for being better than Einstein, and it seems that I really did not follow the wrong mentor, and I must continue to work hard under him.

(End of chapter)