Before the Spring Festival, doctoral student Li Kangping's experiment made significant progress, the process data is very beautiful, and after the Spring Festival, a few more experiments should be able to get satisfactory experimental conclusions.

During the Spring Festival holiday, the tutor told Li Kangping: "The holiday is extended, stay at home, and wait for the notice." ”

Li Kangping obeyed the arrangement, and he stayed in the big villa in his hometown in Guangzhou.

A few years ago, Li Kangping inherited an inheritance, he lived alone and did what he wanted.

Wait, wait, wait, Li Kangping waited from the age of 29 to 30, and waited until the beginning of September, when he finally returned to the laboratory of the School of Physics at Tsinghua University.

The frequency stabilization of the saturation absorption spectrum locks the frequencies of the two lasers at the resonance transition positions of 6^2S1/2, F=4→6^2P3/2, F'=5 resonance frequency negative detuning 11MHz and 6^2S1/2, F=3→6^2P3/2, F'=4, respectively.

The outgoing zero-order diffracted light is set by Li Kangping as the trapped light, and the positive first-order diffracted light is used as the re-pumping light, so that the total trapped light intensity is in the range of 3.7~12mW/cm^2.

The experiment went well, as in Li Kangping's experimental design, the same pair of anti-Helmholtz coils generated the quadrupole magnetic fields required to form the cesium atomic magneto-optical trap and the sodium atomic magneto-optical trap.

"Ness."

Li Kangping pays close attention to the data screen, and everything is under control.

"Huh? Jumped? ”

Suddenly, Li Kangping noticed that the loading rate of the sodium atom magneto-optical trap was a little wrong.

In the next second, a strange light flashed in the laboratory......

……

"Lee, are you asleep? Oh my God, you're asleep! ”

Li Kangping opened his eyes, and he saw a young white girl sitting next to him.

The white girl wears a sassy skullcap, her down-hanging straw-yellow curls swing briskly like waves, her blue eyes are bright and clear, her nose and upper lip line are delicate and well-proportioned, and she wears a tight skirt and curved high heels of boat shoes, her figure is soft and slender.

A large amount of memory information poured into Li Kangping's mind, he rubbed his temples and said in English: "Sorry, Jennifer, I'm too sleepy. ”

"It seems like I'm a boring person, and the jokes I tell aren't funny at all." Jennifer shrugged plaintively.

"Jennifer, stop telling jokes and tell me about your hometown."

"The jokes I tell are really boring, and my hometown is probably even more boring."

Columbia University's lawn is like a huge green carpet, and the autumn breeze of September is pleasant.

Li Kangping and Jennifer sat on the lawn, Jennifer said, Li Kangping listened.

After the memory was fused, Li Kangping brushed his thoughts, oh, I traveled to 1920 a hundred years ago, what is this?

The original owner of this body was also called Li Kangping, the word Zhuxi.

Li Zhuxi, a 20-year-old graduate of Tsinghua University, arrived in New York half a month ago to study at Columbia University.

Tsinghua School offers high school and first- and second-year college courses, and students will study in the United States at all official fees after graduation, and transfer to the third year of American universities to continue their studies.

Li Zhuxi took 8,000 yuan from his family, which was converted into 4,000 US dollars, and he took 4,000 US dollars to the United States and transferred to the third year of Columbia College at Columbia University.

All Chinese students in the United States have received English training before coming to the United States, but many Chinese students in the United States have difficulty integrating into the American context when they first come to the United States, which is equivalent to being half-deaf and half-mute.

In order to quickly get through the language adaptation period, some Chinese students in the United States turn to private English teachers. Jennifer is Li Zhuxi's English personal tutor, for which she is paid $1 an hour.

This is Jennifer's third year at Barnard College, a women's college affiliated with Columbia University.

"I couldn't sleep because of the clattering and whirring of engines on the tracks, and the rumble of freight locomotives." Jennifer seemed distraught, as if she were in the scene she was described.

Li Kangping listened with interest, and he asked, "Your family lives near the railroad tracks?" ”

"The spur of the railroad track was laid later, and my family's house couldn't be moved. When I was 10 years old, my area of home became an industrial town, and suddenly there were a lot of black laborers, who were always talking loudly and laughing. ”

"Are the factories full of black laborers?"

"There are white people, there are anybody. Mr. Lee, it's an hour up, it's time for me to go. ”

"I want to continue to hire you for six hours." Li Kangping took out six dollars.

"Thanks, but I can only accept three hours, I have a class in the afternoon." Jennifer accepted the three-dollar bill and placed it in her black leather card holder trimmed with silver filigree.

Li Kangping smiled: "Can you walk with me?" ”

"Of course."

Li Kangping and Jennifer walked together and wandered around the campus of Columbia University.

"Li, you're making rapid progress, and I've found that you can fully understand what I'm saying, and I can understand what you're saying--- basically."

"Jennifer, you're a good teacher, and your teaching is as good as your beauty."

"Thank you, you have such a sweet mouth. I would like to ask, do you have a Merriam-Webster University Dictionary? ”

"Not really."

"Lee, I think you should buy a copy of Merriam-Webster's University Dictionary and the New York Daily News, and you'd better buy a newspaper every day to read, which will help you learn English and understand the United States."

Jennifer stopped at the door of the on-campus bookstore at Columbia University, pointed to the bookstore and said, "It's sold here." ”

"Listen to you, buy it."

Li Kangping entered the bookstore, paid $5.50 for a copy of the Merriam-Webster University Dictionary and two copies of the New York Daily News, and sat on a bench under a large tree with Jennifer.

"Jennifer, you read the newspaper from the front page until the end of today's employment, and I will meticulously learn your pronunciation and speaking habits." Li Kangping spread out his "New York Daily News" and browsed the text information.

"Keep reading, keep reading, gentleman, your dollars are hard to earn!"

Jennifer was a little helpless, and then read the newspaper aloud: "Milk sells for 15 cents per quart, sirloin steak for 42 cents per pound, butter for 61 cents per pound, fresh eggs for 62 cents per dozen...... Prices in New York have risen by 50 percent, but the average weekly wage in New York has remained the same, and even people with no dollar on them are twice as wealthy as they used to be. ”

Li Kangping asked: "What is the average annual income of the average American family?" ”

Jennifer thought for a few seconds and said, "Hmm...... It seems to be about $1,000, which is a little higher in New York. ”

"Go ahead, Jennifer, next."

"The New York Stock Exchange has a one-day trading volume of 2 million shares, but Wall Street financiers are worried."

The New York Yankees spent $125,000 earlier this year to bring in baseball superstar Babe Luce, who hit 30 home runs in his first season with the New York Yankees. Yesterday, Babe Luce hit a home run again, and a man died on the spot because he was so excited. ”

"President Wilson seems to care more about the new international order he envisions, but do postwar American taxpayers really care about the League of Nations?"

"The evil German emperor fell, but a new power quickly rose in Europe---- the Bolsheviks. Starting today, red flags are not allowed in New York City. ”

Li Kangping asked again: "You seem to hate the German emperor very much?" ”

Jennifer said emotionally: "My brother, he died in the European battlefield, and he was just 21 years old when he died in battle!" A lot of American families have lost their husbands, sons, brothers, this damn war! Yes, I hate the Kaiser, I hate war! ”

Li Kangping said with a complicated expression: "That's right, this damn war." ”

The two talked and talked, and the three hours passed quickly.

"Mr. Li, it's really time for me to go."

"Jennifer, let's have lunch together."

"Don't eat, it's time for me to go to class."

"Jennifer, I'm afraid you're going to faint in the classroom."

"I'm not that vulnerable, I'm stronger than you think. Until next time, Mr. Lee. ”

"When is our next time? Tomorrow? ”

"Not tomorrow, I'm busy all day tomorrow. The day after tomorrow, what do you say? ”

"OK, see you the day after tomorrow."

Li Kangping said goodbye to Jennifer and paced to the campus cafeteria of Columbia University.

The restaurant is minimalist, with portraits of celebrities hanging on the walls. Li Kangping paid 20 cents for a simple lunch, coffee, chocolate and Jerusalem artichoke.

During his undergraduate years, Li Kangping went to UCLA for an exchange year, and he originally planned to go to the United States for graduate school, but he did not succeed, so he stayed in China for graduate school. During his master's and doctoral studies, Li Kangping read a lot of English literature, and his English listening, speaking, reading and writing skills were OK.

After the meal, Li Kangping walked out of the Columbia campus and walked around the neighborhood near Columbia University with road number 100+.

There are many cars and brands on the street, Ford, Buick, Chevrolet, Dodge, Cadillac, Packard, Franklin, Lexington, Brisco, Teppler, Hudson, Mercer, Maswell...... There are at least 100 car brands in the United States today, and most of them are unheard of by Li Kangping.

Li Kangping moved to a towering Ford black cab, pulled the door open, and got into the car.

The driver asked, "Young man, where are you going?" ”

Li Kangping said: "Drive around Manhattan. ”

"I'm confused, where the hell are you going?"

"Let's go downtown, and then drive back here."

"Sightseeing, huh?"

The driver adjusted the spark plug and throttle lever to a three-tenth position, and he pulled the coil and turned the crank vigorously.

Li Kangping asked: "Sir, it's 1920 now, don't you have an electric starting device?" ”

"As you can see, it's not pretended."

Boom, the engine finally roared. The driver moved the spark plug, adjusted the throttle lever to 2:25, and the car started up and drove off 120th Street.

Sitting in this bumpy Ford, Li Kangping looked out the window, carefully observed Manhattan in 1920, and chatted with the driver from time to time.

"The newspaper said that the United States had a national alcohol ban, is it really a ban on alcohol? Don't have a place to buy alcohol? Li Kangping asked.

The driver said, "You know, New York is the City of Freedom, and you can buy moonshine at most grocery stores in New York. Well, it's sold here. ”

"Thank you."

The gridded blueprints divide Manhattan into rectangular blocks, with high-rise buildings, elevated trolleys, and giant electric advertisements flashing on the rooftops of the towers.

Taxis run from Uptown Manhattan to Midtown to Downtown and back down the Hudson River to Morning Heights.

Li Kangping paid to get out of the car, no matter what era it is, we can always get some interesting anecdotes from the mouth of the taxi driver.

A dozen roast chickens swirl in the oven by the window of a bakery restaurant on Morning Street, emitting the enticing smell of blazing burnt aroma. Roast chicken is 35 cents a piece, and there is a long line of people who buy chicken.

Next door to the rotisserie is a pharmacy that sells medicines, soda, women's cosmetics, and light ale--- a drink that removes the alcohol from beer.

Next to the pharmacy is a Chinese-owned laundry, where people come and go, and business is booming. Machine washing can easily damage clothes, and many American families like to send their clothes to hand-washed Chinese laundries.

The Chinese laundry is next door to the grocery store, and Li Kangping said to the grocery store owner, "I need four bottles of Irish whiskey." ”

The grocery store owner doesn't ask who you are or doesn't have to verify your age, you give him dollars and he gives you moonshine.

Mr. Lee paid $40 for four 26-ounce bottles of whiskey and returned to his Columbia dormitory.

The dormitory is a single room, Li Kangping overlooks the outdoors, the downstairs branches and leaves are sparse, the birds are singing and the flowers are fragrant, it is really a good place to go in the middle of the noise.

Li Kangping in the three-sided mirror in the bathroom is wearing a gentleman's hat, a silver-gray suit, a vest and a white shirt, and a twill tie.

"Isn't this the brother who eats with his face?"

After Li Kangping looked in the mirror, he was more satisfied with his appearance.

The amber liquid rippled in the glass, and Li Kangping drank the whiskey.

The post-90s in the previous life, the post-00s in this life, no matter what, this is a new life experience, whether it is a celebration wine or a wine on the road, you have to drink a glass.

Drinking three glasses of whiskey in a row, a huge amount of information poured into Li Kangping's brain, the theory of relativity, artificial nuclear reactions, wave-particle duality, the Compton effect, Bose-Einstein statistics, Pauli's principle of incompatibility, Heisenberg's uncertainty principle, Fermi-Dirac statistics, the Schrödinger equation, the Raman effect, neutrons, positron and negative electron pairs, neutrinos, cyclotrons, nuclear fission, CP-1......

I remember all the academic literature I have read!

Li Kangping stood by the window and looked up at the starry sky, oh, yes, this is the era of bright stars.