Volume 1: Student Life Chapter 419: How much paper can you write on one flight?
"The size of a hadron is about 1 fermion, within which a corresponding number of valence quarks and gluons are confined..."
"In the MIT-bag model, quarks and gluons are trapped in a pocket, usually viewed as a spherical cavity..."
"The confinement effect manifests itself as a boundary condition with a constant energy density B..."
While thinking, Chen Zhou wrote the corresponding formula on the draft paper.
Here, the method is the same as that used by MIT physicists.
That is, the boundary conditions make the color flow zero at the surface, resulting in quantized energy levels.
The energy density B will produce a constant energy term, which keeps this pocket of finite size.
The solution to the gluon motion equation that corresponds to the gluon field pattern in the cavity and satisfies the boundary conditions is nμGμa=0.
Chen Zhou looked at the solution to the equation and habitually tapped his pen.
Then, quickly write next to the equation:
[Where nμ is the normal direction of the cavity surface, Gμa is the gluon field strength tensor, and the lowest mode is calculated as:]
【Transverse Electric JP=1+，xTE=2.844】
【Transverse Electric JP=1－，xTM=4.493】
[From this, we get the low-mass glueball state:]
[(TE)2,0++,2++,M=960MeV;]
[(TE)(TM),0-＋,2-＋,M=1.3GeV;】
【(TE)3,0++,1+-,3+-,M=1.45GeV.】
Chen Zhou took a look at what he had written and circled the last three lines of text with a pen.
Here, the (TE) 3 mode corresponds to the three-gluon glueball.
In fact, under the pocket model, we can go deeper and study glue balls with multiple different quantum numbers.
Physicists at MIT have done this.
There is also a comparison chart of the mass of the rubber ball under the pocket model.
However, Chen Zhou does not plan to conduct in-depth research for the time being.
After all, this was on a plane and it was hard to get into that kind of immersive state.
Moreover, the immersive state is easily interrupted.
Therefore, Chen Zhou’s current idea is mainly to understand the pocket model .
So that you can have a clear idea of what is going on.
Chen Zhou opened the draft paper, picked up a pen, and began to study the lattice QCD theory.
Speaking of which, Chen Zhou is more curious about the research method of this theoretical model.
Because studying glueballs inevitably requires knowing the properties of the quantum chromodynamics vacuum.
This involves non-perturbative quantum chromodynamics and cannot be obtained through standard quantum chromodynamics perturbative calculations.
Therefore, in studying the physics of quantum chromodynamics in the non-perturbative energy region, we start from the first principles of quantum chromodynamics.
The most reliable method at present is the lattice QCD theory.
This is also a numerical calculation method, called Lattice QCD.
When thinking of numerical computing, Chen Zhou thought of what Friedman called computational physics.
Not only did Friedman praise him, Chen Zhou himself also understood that because of mathematics, he was indeed better than other physicists in numerical calculations.
But this is only relative.
After all, there is a saying that most good physicists are also good mathematicians.
Without sufficient mathematical knowledge and computing ability as support, you will not go far in the world of physics.
Just think of Newton and Einstein.
Of course, Chen Zhou and Friedman use different criteria for judgment.
Chen Zhou based his calculations on his own actual measurements, while Friedman based his calculations on the two physics papers.
If you really look at those two papers, Chen Zhou himself knows that it is because of the added bonus of the wrong question collection that he gives people a keen sense of directional judgment.
But from another perspective, the collection of wrong questions belongs to Chen Zhou, so it can also be attributed to Chen Zhou.
So, Friedman’s evaluation is not wrong…
Time passes by under Chen Zhou's pen.
The calculated values were left on the draft paper.
However, as the calculations unfolded, Chen Zhou couldn't help but frown slightly.
Finally, Chen Zhou slowly stopped writing and tapped on the draft paper as usual.
This time, Chen Zhou's order would take much longer.
I took a quick look at every calculation step on the draft paper.
Chen Zhou calculated the whole thing from beginning to end again in his mind.
You know, even lattice QCD theoretical calculations require a lot of parameters.
For example, the mass of quarks, the energy scale ΛQCD, the lattice distance r0, and so on.
The embarrassing problem Chen Zhou is facing now is whether the parameters can meet the corresponding conditions.
After all, theoretical results ultimately need to be verified by experiments.
The uncontrollability and errors of the experiment may lead to the failure of theoretical verification.
This is also one of the reasons why some physical problems in computational physics are difficult to solve.
In addition, there is a lack of corresponding algorithms, inability to perform corresponding analysis of numerical solutions, high complexity and chaotic phenomena.
These are also the reasons why physical problems are still difficult to solve even with the use of computational physics methods.
Just like the Stark effect phenomenon, solving the electron wave function requires a very complex algorithm.
If things go wrong, we can only solve part of the situation.
This Stark effect is also a problem in quantum mechanics.
This means that when atoms are in a strong electric field, the behavior of electrons will change accordingly.
In addition, solving the Stark effect problem sometimes requires the use of perturbation theory in mathematics for approximate solutions.
Of course, the perturbation theory here refers to the perturbation theory in quantum mechanics.
Chen Zhou doesn't like this approximate solution.
What he prefers is the accuracy of the data, or the accuracy of the numerical values.
It's like, if there is a calculation related to the speed of light, most people will use 3.0×10^8m/s.
But in precise calculations, the speed of light is 299792458m/s, and it cannot be wrong at all!
Maybe this is because Chen Zhou was a mathematician...
Therefore, Chen Zhou is a bit picky when using the methods of computational physics.
Of course, this pickyness refers to his calculations of himself.
On the other hand, this has always been Chen Zhou's habit.
If it weren't for this picky habit, he would not have been praised by Mr. Qiu Chengtong as a person with "extremely rigorous calculations."
After reading the draft paper in front of him, Chen Zhou read through all the content about the lattice QCD theoretical calculations.
This time, it wasn't just for viewing.
Chen Zhou began to read and make notes on the side.
However, this comment is a bit confusing.
In Chen Zhou’s own words, the previous calculations were not wrong.
The current calculations are not correct.
However, if you make any slight changes, you have to calculate it again.
When you calculate more, the data will naturally reveal some answers.
The journey from San Francisco back to Boston, from the west coast of the United States to the east coast of the United States, is not short.
But except for the necessary time to go to the toilet, Chen Zhou almost always stayed in his seat, holding a pen and writing row after row of numbers and symbols on the draft paper.
In the past, Chen Zhou didn’t know how much draft paper he could write during a flight.
However, after this voyage, Chen Zhou probably knew it.
There are a total of twenty sheets of densely filled draft paper!
And this time the flight time was just over five hours.
In other words, Chen Zhou filled up about four A4 sheets of draft paper in an average hour!
Although it is a little slower than his usual efficiency.
But it’s not bad.
When getting off the plane, Friedman saw Chen Zhou packing up his draft papers and said in an admiring tone: "Your research efficiency is the most efficient among all the students !"
