Chapter 345: Aren't you sick?

Xu Zhengyang and the others had class in the afternoon, so they didn't go to the library. Everyone separated at the intersection in front of the Nongyuan Restaurant.

On both sides, branches sprouted tender buds. There weren't many, but the little dots of green combined together, and the breath of spring came rushing toward them.

Xu Qingzhou watched the backs of Xu Zhengyang and the three disappear at the intersection, suddenly feeling a bit dazed.

In the second year of university, the greenness on everyone had faded a lot, and even this guy Xu Zhengyang had started walking toward the library.

Moreover, looking back carefully, he found that his own mentality was also becoming younger. Teasing the school beauty Song, getting beaten, or chatting with Xu Zhengyang and the others—the outline of the once dead-silent middle-aged man had gradually disappeared from his memory.

Returning to the library, after sending a message to Song Yao, Xu Qingzhou sank into calculations again.

At 5:30 PM, the sunset was already hanging on the horizon, Economics Academy, 2nd floor.

Han Shiyi, who was just about to go to the cafeteria for dinner, happened to run into Song Yao.

"Junior Sister, haven't seen you for two days. What are you busy with?"

Han Shiyi looked at Song Yao and greeted her with a smile. Who said only boys want to look at beauties? She, a girl, still wanted to stick with pretty girls.

Song Yao said: "Xu Qingzhou is sick, I'm taking care of him at home."

"Oh, oh, it's easy to get sick when the seasons change."

Although she said that, Han Shiyi had already started shipping them in her heart. As she learned more, Song Yao was only cold to them.

But this was precisely the point that was very shippable.

Because it was more in line with the character of a novel's heroine, leaving gentleness to one person.

Han Shiyi invited: "Junior Sister, go eat together?"

"Not eating today, I'm going home." Song Yao shook her head apologetically.

"It's okay, I was just asking." Han Shiyi suddenly remembered that this Junior Sister had a patient at home. Walking out of the Economics Academy with Song Yao, she saw a boy wearing a mask standing at the intersection.

From the figure, it was exactly that very awesome Junior Brother.

Simply greeting Xu Qingzhou, Han Shiyi hurried away.

On this side, Song Yao first touched Xu Qingzhou's forehead to confirm that he wouldn't have a fever again.

Actually, after eating medicine at noon, his body was almost better, but Xu Qingzhou still rubbed his temples and sighed endlessly: "My body is a bit weak, I guess I have to rest for two more days."

The sunset hung on the horizon, painting a large area of clouds. The orange-yellow soft light spread over the earth. Under the gardenia tree with dots of green, two young people stood opposite each other, the shadows pulled by the afterglow intertwined together.

This was the scene seen by the "shipper" Han Shiyi in the distance.

Is this the feeling of being hit by spring?

Damn it, I'm shipping like crazy!

And so, Xu Qingzhou enjoyed two more days of preferential treatment.

This day, Xu Qingzhou lay on the sofa and shouted lazily to the girl who was pouring cat food for Er Miao: "Little Song, pour a glass of water for Xu Laoshi."

Song Yao's crystal-clear eyes stared at Xu Qingzhou. She had reason to suspect that this guy's illness was already cured, and now he was just purely acting.

Just like in the afternoon, she was cooking in the kitchen and, worried about this guy, secretly took a peek, only to see this guy happily teasing Er Miao, full of spirit. When she came out, this guy was in a withered posture again.

However, she still got up, poured a glass of hot water, took a sip herself, found it wasn't hot, and then handed it to Xu Qingzhou.

"You still aren't better?"

Xu Qingzhou touched his forehead: "No, it feels even more serious than the past two days, body aches, no strength... Little Song, peel an orange for Xu Laoshi."

Song Yao went to the dining table to get an orange, peeled it, and threw it directly to him from two meters away. It was slightly off when she threw it.

Xu Qingzhou was quick-eyed and caught it accurately, muttering: "Little Song, it's not that I'm talking about you, remember to throw it accurately next time. If I hadn't been agile, this orange would be gone."

He was just saying this, but found Song Yao staring at him expressionlessly.

"Body weak?"

"..."

"Look, it's all because you took such good care of me, I suddenly feel like nothing is wrong."

*Pu~*

"Wrong, wrong~"

"My waist!"

Xu Qingzhou was pressed onto the sofa and beaten up. 10 minutes passed.

"Lighter."

"Oh, oh, okay."

Xu Qingzhou had a "fawning" expression, one hand rubbing his waist, one hand massaging the school beauty Song's shoulders: "Are you satisfied yet?"

Song Yao nodded slightly, gave a "hmm" in her nose, changed her posture, leaned on the sofa, tapped Xu Qingzhou's chest with her toes, and said slowly: "You can talk about your problems properly now."

"I was wrong." Xu Qingzhou restrained the urge to hold the white feet and had a correct attitude.

"Obviously."

11:30, the two had already finished showering and were huddled in the quilt, planning to rest early today.

"Beat you if you move around again."

Song Yao patted away someone's dog paws. He didn't know how to restrain himself just after getting better.

"I'm already better."

【In one look...】

"You aren't better."

"..."

Xu Qingzhou sighed, lifting a rock only to drop it on his own feet. He shook his head and hugged the girl in his arms.

The bedroom was quiet for a moment, and Song Yao's voice sounded again: "In May, I'm going to Singapore with Professor Li to attend an academic forum."

"Hmm, I can guard the empty room alone."

Xu Qingzhou sighed. Professor Li Daiyue was really good to Song Yao; she could already go everywhere to participate in various economic forums during her undergraduate stage.

At the same time, he pondered, since he was guarding the empty room alone, should he ask for some compensation after she came back.

Just then, the phone rang.

Song Yao: "Jiahui."

"Yao Yao, are you busy?"

Song Yao glanced at Xu Qingzhou: "No, already finished being busy."

Already finished beating him up, nothing wrong now.

"Yao Yao, Guo Ziyang is so busy now, coding with seniors every day..."

After listening to Ding Jiahui finish, Xu Qingzhou roughly understood. Guo Ziyang was too busy during this time, and Ding Jiahui couldn't even make a phone call to cook soup, so she could only find Song Yao to chat out of boredom.

Seeing the slight resentment in Ding Jiahui's tone, Song Yao said: "He has ambition, you should be happy.?"

Ding Jiahui paused, lying on the windowsill, and also felt that what her sister said was right: "Yeah, it's just that he suddenly got busy and didn't have time to eat together... maybe I should get busy too."

The two chatted on and off. By 12:00, Ding Jiahui's roommate wanted to sleep, so the two girls hung up the phone.

What goes around comes around. Xu Qingzhou was enslaved for the next few days, cooking, washing dishes, sweeping, and mopping the floor.

The small interlude of being sick passed, and Xu Qingzhou was fully invested in physics calculations.

In the library, a pile of manuscript paper had already appeared in front of Xu Qingzhou.

In classical quantum theory, the wave function describing a freely moving electron is described as ψ0＝eip·r／, assuming its normalization factor is 1, where p＝mv is the electron momentum.

The Hamiltonian of a charged charge in a magnetic field is: h=1\2m(pqa)

For electrons, there is the equation: h=12m(p+ea)

When there is no magnetic field, the above equation is the equation for a free electron, that is, the wave function at this time can be written as:

【ψ(r，t)=0(r)eiet/\psi】

Through calculation, Xu Qingzhou had already been able to discover information about the AB effect and the topological properties of quantum states, and connections to phenomena such as the quantum Hall effect in condensed matter physics.

However, the specifics still needed detailed deduction.

Currently, condensed matter physics occupied half of the physics world, so much so that Xu Qingzhou had once been involved in a large number of experiments in this area. No way, condensed matter contains too many things.

A more quantum mechanical way of saying it is that for a considerable class of condensed matter systems, the total Hilbert space is the direct product of the subspaces of each particle. As the number of particles increases, the Hilbert space obviously increases exponentially.

But macroscopically, what you see—shaving a little off a piece of material or adding a little to it—doesn't seem to affect the properties of the material, such as intensive quantities.

That is to say, not all parts of this huge Hilbert space are playing a role, and in fact, only a very small subspace is important for real physics.

Condensed matter physics, roughly speaking, is finding this key Hilbert space, writing out a multi-electron Hamiltonian containing interactions based on a certain type of specific material or specific physics, and then solving it by various means.

(End of chapter)