NOVEL NEXT Xueba starts with change
Chapter 419 How much paper can I write on one flight?
Chapter 419 How much paper can I write on a plane?
"The size of a hadron is about 1 Fermi. In this region, a corresponding number of valence quarks and gluons are confined..."
"In the MIT-bag model (pocket model), quarks and gluons are imprisoned in a pocket, which can usually be regarded 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 used by Chen Zhou is the same as that of physicists at MIT.
That is, the boundary conditions make the color flow zero at the surface, resulting in quantized energy levels.
The energy density, B, produces a constant energy term that keeps the pocket finite in size.
And this corresponds to the gluon field mode in the cavity, and the solution of the gluon motion equation satisfying the boundary conditions is nμGμa=0.
Chen Zhou looked at the solution of this equation and tapped his pen habitually.
Then, quickly write next to the equation:
[In which, nμ is the normal direction of the cavity surface, Gμa is the gluon field strength tensor, and the lowest mode obtained through calculation is:]
[Transverse Electric JP=1+, xTE=2.844]
【Transverse Electric JP=1-，xTM=4.493】
[Starting from this, the state of low-quality rubber balls is obtained as:]
[(TE), 0++, 2++, M=960MeV;]
【(TE)(TM), 0-+, 2-+, M=1.3GeV;】
【(TE), 0++, 1+-, 3+-, M=1.45GeV.】
Chen Zhou glanced at what he had written, and circled the last three lines with a pen.
Here, the (TE) mode corresponds to the trigluon ball.
In fact, under the pocket model, it is possible to go deep and study multiple glue balls with different quantum numbers.
Physicists at MIT have done just that.
There is also a comparison chart of the quality of the gumball under the pocket model.
However, Chen Zhou does not plan to conduct in-depth research for the time being.
After all, this is an airplane, and it's hard to get into that state of immersion.
Moreover, the state of immersion is easily interrupted by others.
Therefore, Chen Zhou's current thinking is mainly to understand the pocket model.
It's good to know what you know.
Chen Zhou turned over the draft paper, took a pen, and began to study the theory of lattice QCD.
Speaking of which, Chen Zhou is more curious about the research method of this theoretical model.
Because of the study of glueballs, it is inevitable to need to know the properties of quantum chromodynamic vacuum.
And this, involving non-perturbative quantum chromodynamics, cannot be obtained by standard quantum chromodynamic perturbation calculations.
Therefore, in the study of quantum chromodynamics non-perturbation energy region physics, we start from the first principle of quantum chromodynamics.
The relatively most reliable method at present is the lattice QCD theory.
This is also a numerical calculation method, known as Lattice QCD.
Thinking of numerical calculation, Chen Zhou thought of what Friedman said, computational physics.
Not only Friedman's praise, but Chen Zhou also understands that he is indeed better than other physicists in numerical calculation because of mathematics.
However, this is only relative.
After all, there is a saying that good physicists are mostly good mathematicians.
Without enough mathematical knowledge and computing power as a support, you can't go far in the world of physics.
Just think of Newton and Einstein and you'll see.
Of course, Chen Zhou's and Friedman's judgment standards are not the same.
Chen Zhou is based on his own actual measurement, while Friedman is based on those two physics papers.
From those two papers, Chen Zhou himself knew that it was because of the addition of wrong question sets that he gave people a keen sense of directional judgment.
But from another perspective, the set of wrong questions belongs to Chen Zhou, and if it belongs to Chen Zhou, then it can also be counted on Chen Zhou.
Therefore, Friedman's evaluation is also correct...
Time passed by Chen Zhou's pen.
On the draft paper, the calculated values were left one by one.
However, as the calculation unfolded, Chen Zhou couldn't help frowning slightly.
Finally, Chen Zhou slowly stopped writing, and habitually lit on the draft paper.
This time, Chen Zhou's time will be much longer.
At a glance, every step on the draft paper is calculated.
From beginning to end, Chen Zhou calculated silently in his heart again.
It should be known that even the theoretical calculation of lattice QCD requires many parameters.
For example, the mass of quark, the scale of energy ΛQCD, the distance r0 of grid point, and so on.
The embarrassing problem Chen Zhou is facing now is whether the determination of the parameters can meet the corresponding conditions.
After all, theoretical results ultimately require experimental verification.
The uncontrollability of the experiment and the error of the experiment may cause the failure of the 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, the inability to perform corresponding analysis on numerical solutions, high complexity and chaotic phenomena.
It is also the reason why physics problems are still difficult to solve even with the use of computational physics methods.
Just like in the phenomenon of the Stark effect, the solution of the electronic wave function requires a set of very complicated algorithms to solve it.
If it is not done well, it can only solve part of the situation.
This Stark effect is also a problem in quantum mechanics.
It means that when atoms are exposed to a strong electric field, the behavior of electrons changes accordingly.
In addition, the solution to 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 didn't like this kind of approximate solution.
What he prefers is the accuracy of the data, or the accuracy of the value.
This is like, if there is a calculation related to the speed of light, most people will bring in 3.0×10^8m/s to calculate.
But in precise calculation, the speed of light is 299792458m/s, which cannot be worse at all!
Maybe this is because Chen Zhou is a mathematician first...
Therefore, when Chen Zhou used the methods of computational physics, he was a bit picky.
Of course, this pickiness refers to his calculation of himself.
On the other hand, this is also Chen Zhou's long-standing habit.
If it weren't for this picky habit, he wouldn't have been praised by the old Mr. Qiu Chengtong as a person with "extremely rigorous calculations".
After reading the draft paper in front of him, Chen Zhou read all the content about the theoretical calculation of lattice QCD again.
This time, it's not just watching.
Chen Zhou began to read while making notes.
However, this comment is a bit confusing.
In Chen Zhou's own words, the previous calculation cannot be wrong.
The current calculation is not correct.
It's just that if you make a slight modification, you have to do the calculation again.
When there are too many calculations, the data will naturally reflect some answers.
Returning from San Francisco to Boston, the voyage 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 bathroom, Chen Zhou was sitting on his seat almost all the time, holding a pen, and writing on the draft paper, line after line of numbers and symbols.
In the past, Chen Zhou didn't know how much draft paper he could write on a single flight.
However, after this voyage, Chen Zhou probably knew about it.
There are twenty sheets of this densely packed draft paper!
And the flight time this time was just over five hours.
In other words, Chen Zhou wrote about four A4 draft papers in an average of one hour!
Although slower than his usual efficiency.
But not too bad.
When getting off the plane, Friedman saw the draft paper that Chen Zhou was packing up, and said in an appreciative tone: "Your research efficiency is the most efficient among the students I have ever seen!"
(End of this chapter)
"The size of a hadron is about 1 Fermi. In this region, a corresponding number of valence quarks and gluons are confined..."
"In the MIT-bag model (pocket model), quarks and gluons are imprisoned in a pocket, which can usually be regarded 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 used by Chen Zhou is the same as that of physicists at MIT.
That is, the boundary conditions make the color flow zero at the surface, resulting in quantized energy levels.
The energy density, B, produces a constant energy term that keeps the pocket finite in size.
And this corresponds to the gluon field mode in the cavity, and the solution of the gluon motion equation satisfying the boundary conditions is nμGμa=0.
Chen Zhou looked at the solution of this equation and tapped his pen habitually.
Then, quickly write next to the equation:
[In which, nμ is the normal direction of the cavity surface, Gμa is the gluon field strength tensor, and the lowest mode obtained through calculation is:]
[Transverse Electric JP=1+, xTE=2.844]
【Transverse Electric JP=1-，xTM=4.493】
[Starting from this, the state of low-quality rubber balls is obtained as:]
[(TE), 0++, 2++, M=960MeV;]
【(TE)(TM), 0-+, 2-+, M=1.3GeV;】
【(TE), 0++, 1+-, 3+-, M=1.45GeV.】
Chen Zhou glanced at what he had written, and circled the last three lines with a pen.
Here, the (TE) mode corresponds to the trigluon ball.
In fact, under the pocket model, it is possible to go deep and study multiple glue balls with different quantum numbers.
Physicists at MIT have done just that.
There is also a comparison chart of the quality of the gumball under the pocket model.
However, Chen Zhou does not plan to conduct in-depth research for the time being.
After all, this is an airplane, and it's hard to get into that state of immersion.
Moreover, the state of immersion is easily interrupted by others.
Therefore, Chen Zhou's current thinking is mainly to understand the pocket model.
It's good to know what you know.
Chen Zhou turned over the draft paper, took a pen, and began to study the theory of lattice QCD.
Speaking of which, Chen Zhou is more curious about the research method of this theoretical model.
Because of the study of glueballs, it is inevitable to need to know the properties of quantum chromodynamic vacuum.
And this, involving non-perturbative quantum chromodynamics, cannot be obtained by standard quantum chromodynamic perturbation calculations.
Therefore, in the study of quantum chromodynamics non-perturbation energy region physics, we start from the first principle of quantum chromodynamics.
The relatively most reliable method at present is the lattice QCD theory.
This is also a numerical calculation method, known as Lattice QCD.
Thinking of numerical calculation, Chen Zhou thought of what Friedman said, computational physics.
Not only Friedman's praise, but Chen Zhou also understands that he is indeed better than other physicists in numerical calculation because of mathematics.
However, this is only relative.
After all, there is a saying that good physicists are mostly good mathematicians.
Without enough mathematical knowledge and computing power as a support, you can't go far in the world of physics.
Just think of Newton and Einstein and you'll see.
Of course, Chen Zhou's and Friedman's judgment standards are not the same.
Chen Zhou is based on his own actual measurement, while Friedman is based on those two physics papers.
From those two papers, Chen Zhou himself knew that it was because of the addition of wrong question sets that he gave people a keen sense of directional judgment.
But from another perspective, the set of wrong questions belongs to Chen Zhou, and if it belongs to Chen Zhou, then it can also be counted on Chen Zhou.
Therefore, Friedman's evaluation is also correct...
Time passed by Chen Zhou's pen.
On the draft paper, the calculated values were left one by one.
However, as the calculation unfolded, Chen Zhou couldn't help frowning slightly.
Finally, Chen Zhou slowly stopped writing, and habitually lit on the draft paper.
This time, Chen Zhou's time will be much longer.
At a glance, every step on the draft paper is calculated.
From beginning to end, Chen Zhou calculated silently in his heart again.
It should be known that even the theoretical calculation of lattice QCD requires many parameters.
For example, the mass of quark, the scale of energy ΛQCD, the distance r0 of grid point, and so on.
The embarrassing problem Chen Zhou is facing now is whether the determination of the parameters can meet the corresponding conditions.
After all, theoretical results ultimately require experimental verification.
The uncontrollability of the experiment and the error of the experiment may cause the failure of the 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, the inability to perform corresponding analysis on numerical solutions, high complexity and chaotic phenomena.
It is also the reason why physics problems are still difficult to solve even with the use of computational physics methods.
Just like in the phenomenon of the Stark effect, the solution of the electronic wave function requires a set of very complicated algorithms to solve it.
If it is not done well, it can only solve part of the situation.
This Stark effect is also a problem in quantum mechanics.
It means that when atoms are exposed to a strong electric field, the behavior of electrons changes accordingly.
In addition, the solution to 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 didn't like this kind of approximate solution.
What he prefers is the accuracy of the data, or the accuracy of the value.
This is like, if there is a calculation related to the speed of light, most people will bring in 3.0×10^8m/s to calculate.
But in precise calculation, the speed of light is 299792458m/s, which cannot be worse at all!
Maybe this is because Chen Zhou is a mathematician first...
Therefore, when Chen Zhou used the methods of computational physics, he was a bit picky.
Of course, this pickiness refers to his calculation of himself.
On the other hand, this is also Chen Zhou's long-standing habit.
If it weren't for this picky habit, he wouldn't have been praised by the old Mr. Qiu Chengtong as a person with "extremely rigorous calculations".
After reading the draft paper in front of him, Chen Zhou read all the content about the theoretical calculation of lattice QCD again.
This time, it's not just watching.
Chen Zhou began to read while making notes.
However, this comment is a bit confusing.
In Chen Zhou's own words, the previous calculation cannot be wrong.
The current calculation is not correct.
It's just that if you make a slight modification, you have to do the calculation again.
When there are too many calculations, the data will naturally reflect some answers.
Returning from San Francisco to Boston, the voyage 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 bathroom, Chen Zhou was sitting on his seat almost all the time, holding a pen, and writing on the draft paper, line after line of numbers and symbols.
In the past, Chen Zhou didn't know how much draft paper he could write on a single flight.
However, after this voyage, Chen Zhou probably knew about it.
There are twenty sheets of this densely packed draft paper!
And the flight time this time was just over five hours.
In other words, Chen Zhou wrote about four A4 draft papers in an average of one hour!
Although slower than his usual efficiency.
But not too bad.
When getting off the plane, Friedman saw the draft paper that Chen Zhou was packing up, and said in an appreciative tone: "Your research efficiency is the most efficient among the students I have ever seen!"
(End of this chapter)
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