Reborn and become a Great Scientist

Chapter 150 98 Single Photon Interference Experiments

"Sir, you really shouldn't be doing this..."

Before Chen Muwu finished speaking, the staff of the legation directly slapped himself twice.

"Mr. Chen, I'm really sorry, this time I was obsessed with ghosts and lard.

"You must let me go, little brother. Please don't talk about this matter, but don't tell that Zhu d'Affaires at our legation!..."

The staff snotted and burst into tears, wanting Chen Muwu to forgive him from the bottom of their hearts.

Before that, Chen Muwu, who used to pull the big banner as a tiger's skin every day, did not expect that he would become someone else's big banner this time.

But he really has nothing to do with the staff of the legation in front of him.Press the gourd and pick up the ladle. Although Chen Muwu only needs to write a letter to Zhu Zhaoxin, this person will definitely lose his job, but he left alone, it does not mean that other people in the legation will not repeat what this person has done Dirty things.

In the end, Chen Muwu could only think of a stupid solution, which was to notify the embassy of the list in advance the next time he invited people from China.

As long as the people who don't move me, other people's bamboo sticks, let them beat them however they like!

The staff member of the legation left Cambridge with gratitude.

Before leaving, he still did not forget to make various wishes, saying that next time he would send something good from China, he would never forget to send Chen Muwu a copy.

Unlike this person's verbal promise, Zhao Zhongyao really brought something to Chen Muwu.

Zhao is from Zhuji, and Chen Muwu's hometown, Jiayu, was under the same jurisdiction of Shaoxing Mansion in the Qing Dynasty, so the two can be regarded as fellow villagers.

For their study trip abroad, Chen Muwu's elder brother Chen Muqiao paid for the ferry tickets to the UK, and Chen Muwu single-handedly arranged the tuition and living expenses in the UK.

Therefore, Zhao Zhongyao and Shi Ruwei were very grateful for the help of the Chen family. Under the suggestion of their teacher Ye Qisun, they specially brought a few catties of good tea to Chen Muwu.

"When this tea entered the British customs, it must have paid a lot of taxes, right?"

Chen Muwu recalled that when he first came to England, he was also taxed by the black-hearted British customs because he didn't know why, because he brought some tea.

"Ms. Chen, who said no! With just a few catties of tea, the British customs officer charged me several pounds of customs duties. They are really lions!"

……

After the three of them communicated, Chen Muwu discovered a very embarrassing thing.

That was the two students Ye Qisun introduced to him. Although they called him "Teacher Chen" one by one, their real ages were actually older than him.

Therefore, Chen Muwu felt that he couldn't bear the title of Teacher Chen and couldn't agree to it.

After he tried his best to persuade them, the two finally agreed to either call him "Hanchen" by his nickname, or just call him Mr. Chen.

Now that the two compatriots have come to Cambridge University, the next priority is to prepare for the entrance examinations of various colleges.

Now another problem arises, that is, when Chen Muwu came to the UK last year, he never took the entrance examination for Trinity College.

He belonged to the back door opened by Dean Thomson, and as soon as he arrived in Cambridge, he directly entered the Cavendish Laboratory to start experiments.

Therefore, Chen Muwu didn't know what form the entrance examination would take, and if it was just an interview, what questions would be asked.

However, there is a ready-made solution, that is, he, Chen Muwu, has another student who just passed the entrance test of the Christian College not long ago.

Chen Muwu entrusted Zhao Zhongyao and Shi Ruwei to their Oppenheimer, and asked this senior brother of the Chen family to tutor the two to prepare for the next entrance exam.

Oppenheimer did not refuse, because this was the first task Mr. Chen gave him after he came to Cambridge.

He felt that he had to finish this matter well, and asked Chen Muwu to see if he, an honorary graduate of Harvard University, was a vegetarian.

……

The following Tuesday, after a reasonably sumptuous dinner, the impromptu Kapitsa Club event for the summer holidays quietly kicked off in a room at Trinity College.

Zhao Zhongyao and Shi Ruwei, who just came to Cambridge, may not know what big moves Chen Muwu made in the physics field during the more than a month they sailed on the sea.

But since Oppenheimer said with great interest that he was going to listen to Teacher Chen's lecture, there was no reason for the two of them not to follow.

However, since the two of them are not official members of the Kapitsa Club, they can only attend at the bottom of the room.

And Oppenheimer, who was also not a formal member, got the work of meeting minutes under the arrangement of Chen Muwu.

He held the pen in his hand very excitedly, thinking that he must never miss every word from his teacher's mouth.

Chen Muwu thought, in this club activity, let's talk about exactly what this wave function Ψ is.

Asking Oppenheimer to record is also to make it easier to publish another paper after sorting out the content of this lecture.

Chen Muwu didn't want to touch the problem of proving the equivalence of matrix mechanics and wave mechanics, because this problem is too difficult.

It is always said that Schrödinger, in less than half a year after he proposed the wave equation in 1926, strictly proved the equivalence between his wave mechanics and Heisenberg's matrix mechanics mathematically.

But this is nothing more than a physics myth. The proof method given by Schrödinger is to use the wave equation to solve the energy level and steady-state wave function of the harmonic oscillator, and the result obtained is the same as the conclusion given by matrix mechanics.

Then he brazenly said that his wave mechanics is equivalent to the matrix mechanics of Heisenberg, Born, and Jordan, and can be transformed from one form to another by mathematical transformation.

In fact, at best, he "demonstrated" that these two mechanics are equivalent in physics, and he can only fool many physicists who are not good at mathematics.

In the end, it was proved mathematically that wave mechanics and matrix mechanics are equivalent, but Dirac had to wait until 1930, and then von Neumann could give the final conclusion in 1932.

Obviously, Chen Muwu didn't want to be an unpopular mathematician at this meeting of the Kapitsa Club.

Schrödinger's paper "demonstrating" the equivalence of the two mechanics can be left to Zhao Zhongyao, Shi Ruwei and Oppenheimer, as a gift to the three students.

Chen Muwu thought, since he wanted to establish a sect in the future, he couldn't just rely on himself to fight alone, but also cultivated the students under his command to be successful one by one.

So he decided to get straight to the point and directly talked about the probability wave.

"Presumably, the practitioners of physics who came to this conference today should have more or less read the paper I published in the "Nature" magazine not long ago.

"You should think that the guy named Chen Muwu standing in front of him first created something called a matrix, which made people fascinated and fell into the abyss of mathematics.

"Then he invented a wave equation, which saved people from the abyss of mathematics.

"I believe that many of you have also tried this new equation to calculate the hydrogen atomic spectrum, and got very good results.

"But at the same time, I also know that you can't figure out what kind of wave this new equation, which is completely consistent with the form of the wave equation, is describing? What is it that is waving?

"It is well known that in our world, there are two kinds of waves.

"One is mechanical waves like sound waves and water waves, which vibrate on the microscopic scale through air molecules or water molecules, causing fluctuations on the macroscale.

"The other is the electromagnetic wave proposed by Mr. Maxwell. Since the theory of relativity proposed by Dr. Einstein has been widely accepted, people have abandoned the imaginary medium of 'ether' and accepted that electromagnetic waves are electric fields and magnetic fields A vibration in itself.

"Maybe some of you have brought this new wave equation into the existing theory, thinking that the electron is a wave packet in this equation, and then found that this explanation makes the wave unstable, and the electron quickly will dissipate to infinity.

"But the result in reality is not the case. Electrons are electrons, and the phenomenon obtained after calculation will not appear.

"Now, what I want to point out is that this wave is neither a mechanical wave nor an electromagnetic wave, but a probability wave of a new situation.

"As for the amplitude Ψ of your mind, it is similar to the two waves mentioned above.

"In classical physics, the square of the amplitude represents the strength of the wave. In my equation, the square of the amplitude |Ψ| represents the probability of the particle appearing at that position at a certain moment!"

Chen Muwu originally thought that he must be playing a big push in front of the members of the Kapitsa club this time.

But after he talked for a long time, the faces of the people in the audience did not show the shocked face he expected, but most of them were ignorant.

After a while, Kapica, the chairman of the club, raised their questions on behalf of other people: "Chen, can you please explain in detail what is this wave equation about? The probability of this particle appearing , and how should we understand it?"

I was careless, I talked about a lot of theoretical knowledge, and as a result, my colleagues who have been in the laboratory these days may not understand at all.

Now he misses his former roommate Dirac a little bit, if that unsmiling Englishman is here, he will definitely understand what Chen Muwu is talking about.

"One of the simplest explanations of what this probability is is that electrons are everywhere in space, and that at the same moment an electron could be either in my presence or in Mr. Kapitsa's."

"Chen, your statement is really ridiculous." Kapitsa, who hadn't sat down, immediately put forward a different opinion. "At a certain moment, the position of the electron must be fixed. The example you just gave, In fact, it is very easy to know where this electron is. You only need to place Geiger counters in the entire space. If it is true that there is only one electron in the entire space as you said, then there can only be one Geiger counter. The leather counter can make a sound."

Kapitsa didn't know that he was hitting the right spot, and just brought up the matter of wave function collapse.

But Kapica raised the issue of this observation, and now Chen Muwu felt that he could no longer follow the original plan.

He planned to continue talking about the abandoned "ghost field" proposed by Einstein in order to find a wave theory for his imaginary light quantum.

But now he feels that these experimental physicists may still not understand if he talks about purely theoretical things without giving specific physical images.

Fortunately, Chen Muwu had already made two-handed preparations. He turned around and erased the three or five lines of formulas written on the blackboard, and instead drew pictures on them.

When he wrote the word "light" on the display screen, occluders, and parallel lines with arrows, people with a discerning eye could already see that Chen Muwu drew a schematic diagram of Thomas Young's double-slit interference on the blackboard.

"I think I can use another experimental phenomenon to answer the question you raised.

"The double-slit interference experiment is a famous optical experiment conducted by Thomas Young, a fellow of the Royal Society, in the early nineteenth century. It was this experiment that finally overturned Sir Newton's theory of particles of light. Since then, people began to Believe that light is also a wave.

"At the beginning of the [-]th century, in order to explain the experimental phenomenon of the photoelectric effect, Dr. Einstein re-proposed the concept of light quantum, which was finally verified by Professor Millikan's precise photoelectric effect experiment and the gamma ray scattering experiment early last year.

"Now let's reconsider this experiment. Suppose we turn down the brightness of the light source as much as possible, so that the light source only emits one photon at a time, and make sure that during the process of this photon passing through the slit to the screen, no A new photon will be emitted.

"After accumulating photons one by one for a long period of time, if we take the photosensitive film on the screen to develop an image, what kind of pattern will the photo show? Will it still show light and dark? Alternating black and white interference fringes?"

Chen Muwu paused here to give everyone enough time to think.

The people in the arena chattered and discussed, and finally they barely reached a unified opinion, that is, there will be no interference fringes on the photographic film.

"It's just that, unfortunately, the answers you gave are all wrong.

"Fifteen years ago in 15, Geoffrey Taylor, now a Fellow of the Royal Society, was then a student at our Trinity College, and was the Director of the Cavendish Laboratory, now Trinity College An experiment concerning optics was being carried out by Sir Chief Sir Thomson.

"At that time, Brother Taylor used a gas lamp as a light source, and several pieces of glass blackened by soot were placed in front of the light source.

"The reason why he did this is to ensure that the light will become weaker every time it passes through a piece of glass, so as to test whether there will be light fluctuations under low-light conditions.

"This experiment lasted for three full months, and fluctuations were still found in the final developed photographic negatives.

"Although the experiment conducted by Brother Taylor was not double-slit interference but needle tip diffraction, I think that if this experiment is reproduced and the needle tip inside is replaced by two slits, the corresponding experiment will also appear. Phenomenon."

"This……"

No one expected that Chen Muwu would come prepared. For a lecture at the Kapitsa Club, he would even find out a student paper written 15 years ago.

After a long time, it was still Kapitsa who stood up to disrupt the situation: "Chen, but this experiment cannot guarantee that, as you said, there is only one photon in space at a time."

"Mr. Kapitsa, in fact, this matter is guaranteed."

Chen Muwu turned around while speaking, and drew a schematic diagram of a box on the blackboard.

"As early as four years before the first experiment appeared, Dr. Einstein had proposed the light quantum hypothesis, but Taylor's paper did not mention the light quantum.

"But fortunately, he gave detailed experimental data, and we can make a rough estimate.

"According to his statistics, the energy reaching the photographic film per second is 5 x 10 joules.

"Because the light emitted by the gas lamp is light blue, the wavelength of the light is approximately 500 nanometers.

"Because ε=hν, it can be calculated that the number of photons arriving on the photographic film per second is about 100 million.

"Statistical speaking, that is to say, every one millionth of a second, a photon passes through layers of obstacles and hits this photographic film.

"Using this time interval multiplied by the speed of light, you can get the distance between the two photons one after the other, which should be about 300 meters.

"And the length of his entire experimental obscura is only less than two meters. That is to say, statistically, there will only be one photon in the entire experimental space at the same time."

Chen Muwu finally concluded: "As long as only one photon exists in the entire experimental space at the same time, the interference behavior of light is the possibility of photon interaction.

"Therefore, the appearance of interference fringes is the result of the accumulation of many independent behaviors of photons. The bright area of ​​the interference fringes is the area where photons are more likely to arrive, while the dark area is the area where photons are less likely to arrive.

"As for the meaning of the arrival possibility of this photon in physics, if I can't think of any surprises, it is what I call probability, which in turn shows that light waves are a kind of probability waves.

"If the photons in this experiment were replaced by an electron source, I think the same result should appear.

"That's why I say that probability is what this wave equation really means."

There is actually a loophole in Chen Muwu's speech. He just made a statistical average statement, and did not confirm conclusively that there is only a single photon in the same space and at the same time.

In fact, no matter the single-photon interference experiment in the strict sense or the single-electron interference experiment, physicists can completely complete it in the laboratory after the single-electron source and single-photon source appeared in the 70s. do it.

Before that, single particle dry shot experiment can only be an ideal thought experiment.

Moreover, this thought experiment can not only prove that the wave function is a probability wave, but also obtain the uncertainty principle to a certain extent.

However, Chen Muwu felt that it is better not to bring out this thing that caused Bohr and Einstein to quarrel for decades in the original time and space.

He has come up with a shocking quantum mechanics, and the physics community needs to take a few breaths to digest his recent papers.

Zhao Zhongyao, who sat at the end of the venue, asked Shi Ruwei: "Do you understand?"

The latter shook his head frankly: "I only know about the double-slit interference that Mr. Chen mentioned in his lecture, and I also know about the photon he proposed, but regarding the wave function, although Mr. Oppenheimer once mentioned Several times, but I haven't had time to understand it deeply. When it's over, let's borrow Mr. Oppenheimer's notes and study them carefully. If there is anything we don't understand, we can ask Mr. Chen for advice."

Although other people in the venue had understood the wave equation, they, like Zhao and Shi, were ignorant of what they heard.

However, some people have other thoughts in their hearts. They are thinking about whether to carry out the single-photon double-slit interference experiment mentioned by Chen Muwu when they return to the laboratory.

Although the members who remained in the auditorium were still in a superimposed state of shock and bewilderment, Chen Muwu's lecture today was over.

He wiped clean the blackboard behind him, wiped off the chalk shavings on his body, and planned to pack up the things on the table and leave.

If you don't leave now, when these people react and surround themselves completely to ask questions, then you won't be able to run away any more!
At this moment, the door of this conference room was suddenly pushed open.

It was the first time for Chen Muwu and everyone present to see the calm and calm Dirac lose his composure in the past.

And it was also the first time they heard that so many words came out of Dirac's mouth in one breath.

Dirac was notoriously taciturn.

Because he is usually unsmiling, he said too little in the process of getting along with everyone, only a few words every time.

So in St. John's College, Cavendish Laboratory and Kapitza Club, a strange unit named after Dirac's surname appeared.

One Dirac equals one word spoken by a person in one hour.

And one Kapitsa is probably equal to thousands or even tens of thousands of Diracs.

Chen Muwu didn't expect that he was still thinking about Dirac in the lecture just now, but his former roommate appeared in front of him in a timely manner.

Dirac went straight to Chen Muwu, took a few quick breaths, and after adjusting his breathing, he said: "Mrs. Brown said that you have moved out of her house. After I found out that you were at the Kapiza Club, I came here in a hurry. here.

"Chen, I have been reading all your previous papers at home this summer, and I, I found one of your mistakes!"

(End of this chapter)