I just want to be a quiet scholar

Chapter 205 Teaching Experience
The Michelson interferometer uses the sub-amplitude method to generate double beams to achieve interference, and has a certain position in modern physics.

Shen Qi is doing this experiment, which is one of several basic physics experiments.

Transfer the beam expander to the outside of the Michelson optical path, adjust the helium-neon laser bracket, cooperate with the light target to make the beam parallel to the table of the instrument, and control the distance from the entrance and exit points of each optical mirror to the table to be about 70mm...Shen Qi is strict Executed according to the experimental operation process, this optical basic experiment of modern physics is not difficult, and the test is patience and carefulness.

After recording the raw data, Shen Qi quickly calculated the wavelength of the laser and the refractive index of the air, and handed the recording paper manuscript to an experimental assistant in the Academy of Sciences.

The young experimental assistant checked Shen Qi's recording paper and nodded, "OK, there's nothing wrong."

"Senior brother, you are also in charge of the comprehensive design experiment?" Shen Qi asked.

"Yes, Teacher Ren has already explained it." The experimental assistant seemed to respect Professor Ren very much.

"What about researching innovative experiments?" Shen Qi asked again.

The experimental assistant smiled and said, "I'm still in charge. All in all, you can find me for undergraduate experiments."

"Thank you bro, by the way, what's your name bro?" Shen Qixin said that Mr. Ren was very energetic, and he arranged my physics experiment in minutes.

"My name is Qin Hao, and I'm currently in the second year of graduate school." The experimental assistant said, and then asked humbly, "Shen Qi, let me ask you something, how does the Princeton interview work?"

"It's very simple, just blow water with the foreigner interviewer. The interview time is usually about 1 hour, 45 minutes for English and 15 minutes for Chinese."

"These foreigners are very good now, and they speak Chinese very well." Shen Qi said, passing on his experience.

"Just blowing water? The interviewer doesn't investigate academic issues?" Qin Hao asked again.

"Brother Hao, I don't know how other people interview, I can only talk about my own interview experience."

"That American interviewer praised me at the beginning, saying that my data on paper was excellent, and then asked me, hey, Shen, did you have any wonderful and special experiences?"

"I didn't have any wonderful and special experiences, I just recalled my past, from high school to sophomore year, and then a few days later, I received an offer from Princeton."

Shen Qi patiently told Qin Hao about as many interview details as possible to help each other. The next two physics experiments had to be coordinated by Qin Hao: "So, Brother Hao also wants to go to Princeton?"

"Having this idea, I want to go to the Ivy League for a Ph.D."

"But Princeton is too hard to apply, maybe I should be Penn or Cornell."

Qin Hao said with admiration: "It's still Shen Qi, you are the best. In the second year of sophomore year, I got an offer from Princeton, and an offer from the Department of Mathematics at Princeton."

Shen Qi said: "The interview procedures of those schools in the Ivy League are estimated to be similar, mainly to test the oral expression ability of applicants."

"When communicating with the interviewer, you should avoid incoherence, incoherence between the foreword and the rest, and the logic is confusing. The topic of the communication is not the focus, but the confidence and calmness of the communication. Personal opinions are for reference only." At this time, Shen Qi was more like Is an experienced brother.

"Thank you for sharing!" Qin Hao said gratefully, he understands the written process of applying for a prestigious Ivy League school, and the information on the Internet is not true or false for such things as interviews.

Of course, the most reliable consultation channel is to ask Shen Qi, who has just attended the Princeton interview and passed the interview.

Under the arrangement of Professor Ren and the specific coordination of Qin Hao, Shen Qi participated in the comprehensive design experiment of the Institute of Physics the next day.

It was also an optical experiment. Shen Qi named the experiment "Telepathy Between Photons" and listed the required experimental instruments.

Different from the basic experiments that model the fixed procedure operation, the comprehensive design experiment requires the experimenter to design the scheme by himself.

The experimental apparatus Shen Qi applied for was very simple, one light source emitter, two detectors, several ordinary lenses and one half-mirror.

Under Qin Hao's supervision, Shen Qi started the "Telepathy Between Photons" experiment.

Shen Qi carefully adjusted the light source transmitter, continuously reducing the power of the incident light, until it finally emitted extremely weak light and let it pass through the semi-mirror.

A half mirror is a special mirror that allows half of the light to pass through and the other half to be reflected.

The incident light is divided into two sections by the semi-mirror, and then the ordinary lenses are used to change their travel routes respectively, and finally reach the photon detector.

At this stage, the experiment has actually entered the field of quantum mechanics. The question to be solved is, what is light?

Newton believed that the essence of light was tiny particles invisible to the human eye, while Huygens believed that the essence of light was a wave.

The two bigwigs and their followers have been arguing for more than 100 years and still have no outcome.

It wasn't until Thomas Young's famous double-slit experiment that conclusive proof that light was a wave was obtained.

However, the debate continued. Soon after, Einstein stood up. He stood by Newton and argued that light is particle-like. The theory of light quantum was born, and a new era of physics was opened.

Now everyone knows that light has wave-particle duality.

Volatility and particle nature are two extreme opposites, just like the two sides of a coin, we can only see one side of it, but we cannot deny the existence of the other side.

When the wave nature and particle nature of photons appear is like flipping a coin, half to five, completely random. The physics term is called quantum correlation, which is the theoretical basis for the setting of quantum cryptography.

Quantum cryptography is more high-end than the Virginia cryptography used by girls. The elective course "Cryptography" of the Department of Mathematics only briefly described a few sentences. Shen Qi's research is relatively shallow, which is a very applied field.

Shen Qi operates the experimental apparatus to receive photons through two different detectors.

The photons received by the wave detector are wave-like, and the photons received by the particle detector are particle-like.

In fact, these photons come from the same weak light source, and after being split by the half-mirror, the characteristics of the periodic particles depend on the properties of the detector.

After the experiment is done, Shen Qi can call it a day. He copied the "time-delayed selection experiment" of contemporary physicist Wheeler, thoroughly proving the wave-particle duality of light.

Whether it is Einstein or Bohr, the quantum physics giants in the early 20th century put forward theoretical directions and insights, but due to the experimental conditions at the time, they could not be perfectly proved by experimental data.Even the most basic quantum physics experimental instruments in the 21st century were like artifacts in Einstein's time.

Shen Qi prefers to think that photons have twinning properties. His experiment is not over, and he continues to experiment with twin photons.

Twin photons are two photons vibrating in the same direction, as if the photons were exchanging instantaneous information "telepathically" with other photons in the distance.

"Brother Hao, my comprehensive design experiment is over. I can only do this step. The research on high-speed quantum computers is beyond my ability." Shen Qi turned off the experimental instrument, signed the recording paper, and handed it over to Qin Hao.

"It's also beyond my ability." Qin Hao took Shen Qi's experimental record sheet and signed it. After that, he would report it to the teacher of the Academy, and write a preliminary comment to Shen Qi as an experimental assistant.

Shen Qi completed two physics experiments in two days, and the last one left to study innovative experiments, which requires some preparation time.

(End of this chapter)