Chapter 247 Superconductivity is questioned? Li Qiwei takes action!
The phenomenon of superconductivity is like a hurricane, instantly setting off huge waves in the sea of physics.
When the paper was published, the first reaction of most physicists was that it was impossible, absolutely impossible.
This is completely inconsistent with common sense.
According to the explanation of classical thermodynamics, the resistance of metals is caused by thermal movement.
When electrons move in metal atoms, they collide with thermally moving metal atoms, so the energy is reduced and macroscopically, there is resistance.
If the temperature drops to absolute zero, then the thermal motion of all atoms stops, and of course there is no resistance.
But now Bruce's doctoral student's paper shows that when mercury is 4.19K and below, the resistance will completely become zero.
This is like a fantasy!
4.19K and 0K are not the same concept and level at all.
Many people think that the experiment was done wrong, or there was a measurement error.
"Professor Bruce is a little anxious. Such experimental results that obviously violate logic should not be published."
"I have seen this paragraph in Bohr's notes, but I didn't expect that Bruce The professor really did it, I thought it was just a casual comment."
"How can the resistance be zero? The most important thing in physics is all kinds of perfect phenomena!"
"It is probably an experimental error. The resistance just became extremely small and the instrument did not measure it."
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Many physicists have publicly stated that there must be problems with Qian Wushi's discovery of superconductivity.
Of course, the big guys have not spoken publicly yet, because they are cautious and must repeat the experiment first.
University of Berlin, Institute of Physical Chemistry.
Nernst, the master of thermodynamics, is directing his students to repeat the experiment of Master Qian.
"I asked you to do this experiment, but you guys forgot about it."
"I really don't know what to say."
" A result that shocked the academic world has quietly slipped away from your hands."
It turns out that at the first Bruce Conference, Li Qiwei also suggested that Nernst measure the simple properties of matter at extremely low temperatures.
Because the specific heat of a solid is troublesome to measure, it is far less simple than resistance.
But Nernst apparently didn't care.
And now, the discovery of superconductivity is like a heavy hammer hitting his heart.
Nernst prays now that no one sees this paragraph in Bohr's notes, otherwise he will definitely be scolded for being stupid.
A few doctoral students were trembling and didn't dare to talk back, but they complained in their hearts:
"If you keep saying casual things, we will be exhausted to death."
"I can't even finish my own research, so how can I have time to do other things."
However, they definitely don't dare to say it.
Honestly install the experimental equipment and prepare to repeat the low-temperature resistance experiments of mercury, tin, and lead.
With Qian Wushi's paper as reference, the experiment went quickly.
Nernst, as the current leader in the field of thermodynamics, has the most advanced resistance meter in the world in his laboratory.
However, the test results still made him unbelievable and excited!
The resistance of metal has really dropped to zero!
Of course, there is another possibility.
That is, the resistance is not actually zero, but extremely small, so small that it exceeds the limit of the instrument and cannot be measured by the instrument.
But there is no difference.
Physicists are not mathematicians, and they do not need to pursue mathematical limits and perfection.
For the property of resistance, there is not much difference between 0Ω and infinitely approaching 0Ω.
Leave the rest to theory.
Now that the phenomenon of superconductivity has been discovered, the next step must be to study its mechanism.
Ten days after the publication of the superconductivity paper, the Nernst team published a repeat of Qian Wushi’s experiment in a German academic journal.
The paper proves with absolutely accurate data that metal resistance does indeed become zero at extremely low temperatures.
Nernst openly supports superconductivity!
Boom!
The physics world went crazy instantly.
As a big figure who attended the first Bruce Conference, Nernst was even more authoritative than Li Qiwei in the field of thermodynamics.
A small resistance measurement, with his guarantee, there will be no problems with the experimental results.
Although some physicists have questioned it, thinking that the resistance may be too small and cannot be measured.
But Nernst replied: "The resistance meter in my laboratory can measure to the order of 10^-15."
"This order of magnitude, I think, is no different from zero. ."
"Of course, maybe in the future, there will be more advanced resistance meters."
"But I think it still can't measure the resistance of superconductors."
In real history, even in Ridgway's time, there has been no debate about whether the resistance of superconductors is strictly zero, or infinitely close to zero. There is no conclusion.
Some physicists have done experiments to allow electric current to run continuously in superconductors.
The current has learned. After running for two and a half years, there is still no sign of weakening.
According to the most accurate data, the resistance of superconductors is less than the order of 10^-21.
This is an extremely small level, and it is not much different from zero.
Of course, there is a circular argument problem.
However, none of this affects the practical application and great significance of superconductivity.
Nernst’s paper was like a reassurance, which made Qian Wushi and the other two people breathe a sigh of relief.
Li Qiwei was calm and composed, as if he had everything under control.
This made Qian Wushi and others extremely envious.
“When can we have the calm state of mind of a professor?”
Bohr and others were envious.
At this time, Qian Wushi and the three of them have met the requirements for doctoral graduation.
I am simply envious of others.
At this time, Li Qiwei said: "Fifth Division, Huzhou, Huaining, don't think you can relax just because you discovered the superconducting phenomenon." "There are still many unknown problems that need to be solved."
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“You can think about it differently. Since the resistance is zero, it means that the function of the current has changed.”
“Electricity and magnetism are one, so will the magnetic induction intensity change? ? ”
“These are very good research directions.”
In real history, in 1933, German physicist Meissner discovered another important property of superconductors:
When a metal is in a superconducting state, the magnetic induction intensity inside it is zero.
This means that magnetic fields cannot pass through superconductors at all.
Superconductors are 100% diamagnetic.
Physicists call the phenomenon of superconductors being completely diamagnetic called the "Meissner effect".
Later generations will judge whether an object is a superconductor by seeing whether it satisfies both zero resistance and the Meissner effect.
A conductor with zero resistance alone cannot be called a superconductor!
However, in this era, research has not yet reached this point.
Qian Wushi and others looked at Li Qiwei excitedly. The instructor gave them a new direction.
With such a mentor, I will be more motivated to do experiments.
At this time, Li Qiwei added:
“These days, I am also studying the mechanism of superconductivity theoretically and predicting its future research direction.”
“I will make a short comment. By then, superconductivity research will be a major feature of our King’s School.”
Everyone was excited after hearing this.
This is equivalent to them opening up a field, just like Professor Roentgen discovered X-rays.
No matter who makes other achievements in superconductivity in the future, it will be inseparable from their contributions.
On September 10, 1910, Li Qiwei published a signed article in "Nature".
He first explained the mechanism of superconductivity.
“I think the phenomenon of superconductivity is a state of dynamic equilibrium.”
“Professor van der Waals of the Netherlands once proposed that there is an interaction force between molecules.” (Van der Waals forces)
"But I think that there is a similar force between atoms."
"This force keeps the atoms from scattering, but brings them together to keep them fixed." Structure. "
"Under normal circumstances, atoms will undergo thermal motion, but as the temperature decreases, the thermal motion also weakens."
"When the temperature is below a certain threshold, The force generated by thermal motion is lower than the force between atoms. "
"At this time, the force between atoms suppresses the thermal motion, causing the atoms to enter a static steady state, thus producing the superconducting phenomenon. .”
Immediately afterwards, Li Qiwei made a theoretical analysis:
“Therefore, I think high-temperature superconductivity is completely possible.”
“Existing superconductors need to be produced at extremely low temperatures. can be produced, which limits its application."
"But as long as we find a suitable chemical structure to make the interatomic or intermolecular force strong"
"then even at high temperatures. The thermal motion will also be suppressed by this force, resulting in superconductivity. ”
Finally, Li Qiwei proposed the next research direction on superconductors:
1. Superconducting materials.
The superconductors discovered so far are all metal elements, so alloys, metal compounds, inorganic substances, and organic substances, will they also have superconducting phenomena?
2. High temperature superconductivity.
The ideal state is to find a superconductor at room temperature.
3. Superconductivity theory.
The theory of interatomic forces is only a macroscopic summary, and more detailed principles require further in-depth study.
When Li Qiwei’s paper was published, everyone was shocked.
Bruce actually directly proved the existence of superconductivity theoretically.
While other research groups continued to repeat Qian Wushi’s experiments in an attempt to discover any anomalies, he had already explained superconductivity from a theoretical level.
Is this the strength of the world's number one physicist?
It’s so scary!
At this moment, those who were skeptical of Li Qiwei had to admit a fact.
That is, although Bruce has published no new results recently, his strength has not declined at all.
“My God, superconductivity has just been discovered, and the road ahead has already been paved by Bruce.”
"It's terrible. It's really terrible. If Bruce had discovered X-rays, Laue would probably have nothing to do with him."
"Everyone who studies superconductivity in the future will read Bruce's article. It was carried out in the shadows.”
But many people also raised doubts. They did not question the correctness of the article, but questioned Li Qiwei’s character.
“The phenomenon of superconductivity was discovered by Bruce’s students, but now he has published a summary, which is a bit of a grab for the students’ achievements.”
“Yes, Bruce has not made any achievements recently, has he? I feel anxious, so I want to take advantage of the students.”
Faced with these doubts and rumors, Bakra and others subsequently leaked the contents of the conference.
It immediately caused an uproar.
Everyone discovered that without Bruce, his students would have almost missed superconductivity.
It can even be said that Bruce was the discoverer of superconductivity.
Without his foresight, this experiment would never have begun.
Without his persistence, superconductivity would not have been discovered.
To some extent, superconductivity can be regarded as Bruce's achievement.
Just thinking about it makes it even scarier.
Bruce can now think of a topic at random and leave it to his doctoral students to do it, and he will get a Nobel Prize-level result.
Is there anything more outrageous than this?
He didn't even focus on superconductivity, but simply pointed the direction.
Some people even jokingly said: "If Professor Bruce is energetic enough, he may be able to win all the Physics Nobel Prizes by himself."
Then, everyone thought of an even better idea. Unbelievable things.
It seems that Bruce has never made a mistake or missed a beat since his debut.
Quantum theory, relativity theory, predicting the nature of X-rays, superconductivity.
Everyone can't help but ask: Bruce, can't you be wrong?
(End of this chapter)