Chapter 130 Atomic Research and Quantum Mechanics
After coming out of Thomson's office, Li Qiwei started busy work.
Li Qiwei was writing his doctoral thesis while sorting out the development history of atomic physics.
This is a habit he developed in his previous life.
He likes to first grasp the development of physical theories from a macro level and clarify the sequential relationship between various theories.
Only in this way, during the learning process, you will not be dazzled by the names of various characters and doctrines, and cannot distinguish the key points.
The development of the theory of relativity is relatively simple and clear, and there is nothing much to say.
However, quantum mechanics and atomic structure are very complex, and most masters have emerged.
In 400 BC, the Greek philosopher Democritus proposed the concept of [atoms]. He believed that everything is composed of atoms.
In the 16th and 17th centuries, after the natural science system was established, scientists confirmed through experiments that atoms are a real substance.
For some time thereafter, atoms remained the domain of chemists.
In 1789, the French chemist Lavoisier defined the word atom. Since then, the atom has been used to represent the smallest unit in chemical changes.
In 1803, the British physicist and chemist Dalton founded the famous atomic theory based on summarizing the results of his predecessors.
This theory holds that atoms are extremely small solid spheres that are uncharged and have nothing inside.
Dalton also measured the masses of different atoms. He took the mass of the hydrogen atom as 1 and stipulated the relative mass of other atoms compared to the hydrogen atom.
Of course, his measurement results were very rough, but they also inspired people's enthusiasm for studying atomic structure.
In 1827, the British botanist Brown used a microscope to observe that dust would move irregularly on the water.
This further proves the particle theory, a phenomenon also known as Brownian motion.
In 1877, De Sauerkes proposed that Brownian motion is caused by the thermal motion of water molecules.
It is worth mentioning that, based on de Sauerkes, part of Einstein's current doctoral thesis is to explain Brownian motion.
He also theoretically proved that atoms are a real entity.
Although there are many new phenomena, the view that atoms cannot be divided again has been influencing physicists since Dalton.
It was not until 1897 that Thomson discovered the electron, which proved that there is a subdivided structure inside the atom.
The atom itself is uncharged, but the electrons are negatively charged, indicating that there is something positively charged inside the atom.
They exactly neutralize the negative charges carried by electrons, making the atoms neutral.
Therefore, the study of the internal structure of atoms has attracted many physicists to join.
Real history:
In 1911, Rutherford used a scattering experiment in which alpha particles bombarded gold atoms, proving that the interior of an atom is divided into electrons and nuclei. (Now proposed by Li Qiwei)
In 1913, the British chemist Soddy proposed the concept of isotopes.
He believed that there are atoms with the same position in the periodic table but different relative atomic masses.
Immediately afterwards, Thomson invented the mass spectrometer and discovered dozens of isotopes of different elements.
In 1919, Rutherford bombarded the nitrogen nucleus with alpha particles and discovered that the nucleus is composed of protons.
In 1932, Rutherford's student, the British physicist Chadwick, bombarded the beryllium nucleus with alpha particles and discovered the existence of neutrons.
Physicists then figured out the nature of isotopes, that is, atoms have the same number of protons but different numbers of neutrons. These atoms are called isotopes.
Later it was discovered that there are three natural isotopes of uranium atoms: U234, U235, and U238.
Among them, U235 is the most important isotope, affecting the world.
In 1939, German physicist Hahn discovered the phenomenon of nuclear fission by bombarding uranium nuclei with neutrons.
At this point, the structure of the atom has finally been clarified.
Atoms are composed of a positively charged nucleus and negatively charged electrons.
The nucleus is composed of positively charged protons and uncharged neutrons.
During this period, along with the study of atomic structure was the establishment and development of the quantum mechanical framework.
In 1900, Planck proposed quantum theory. (Now proposed by Li Qiwei)
In 1905, Einstein proposed the light quantum hypothesis to explain the photoelectric effect. (Now proposed by Ridgway)
In 1909, Einstein proposed that light has wave-particle duality, which was his greatest contribution to quantum mechanics. (Now proposed by Ridgway)
In 1913, Bohr proposed the quantized orbit of electrons, laying the foundation for the development of quantum mechanics.
In 1924, de Broglie proposed the concept of matter waves, believing that physical particles also have wave-particle duality.
In 1925, Heisenberg created matrix mechanics, which was the first version of quantum mechanics.
In 1925, Pauli proposed the Pauli Exclusion Principle.
In 1926, Schrödinger founded wave mechanics, which was the second version of quantum mechanics.
In 1926, Dirac proved that wave mechanics and matrix mechanics are mathematically equivalent.
In 1926, Born proposed a probabilistic interpretation of the wave function, which later became the "Copenhagen interpretation".
In 1927, Heisenberg proposed the uncertainty principle.
In 1928, Dirac combined quantum mechanics and special relativity to create relativistic quantum mechanics, laying the foundation for later generations of quantum field theory.
In 1935, Schrödinger proposed the famous thought experiment "Schrödinger's Cat", which extrapolated quantum behavior from the microscopic world to the macroscopic world.
In 1948, Feynman created the path integral form of quantum mechanics, which was the third version of quantum mechanics.
It can be said that the period from 1925 to 1928 was the peak development period of quantum mechanics.
During this period, a most important event occurred. The group headed by Einstein and Schrödinger, and the Copenhagen School headed by Bohr.
With regard to quantum mechanics, at the Fifth Solvay Conference in 1927, the most exciting and shocking showdown in the history of physics since 2000 broke out.
The famous "God does not play dice" was spread from that meeting and has been talked about by countless future generations.
After the theory of quantum mechanics was fully mature, the study of atomic structure continued to move forward.
Physicists discovered the weak force in the 1930s and the strong force in 1947. Both of these are forces related to atomic nuclei.
And thus explains the essential principle of radioactive decay of matter.
In the mid-to-late 20th century, physicists discovered that protons and neutrons are composed of smaller structures, namely quarks.
During that period, quantum field theory dominated the world, including quantum electrodynamics, quantum chromodynamics, electroweak theory, the standard model, etc.
In his later years, Einstein was committed to a grand unified theory. He wanted to unify only gravity and electromagnetism.
Because weak force had not yet been recognized and strong force had not been discovered at that time.
A true grand unified theory should unify the four basic forces of gravity, electromagnetism, strong force, and weak force.
In future generations, physicists will only unify the electromagnetic force and the weak force, which is the electroweak theory.
The next step is to try to unify the powerful forces and complete the so-called weakened version of the grand unified theory.
As for unifying gravity, it is too difficult.
This is also the reason why Einstein failed. He chose the most difficult cup of love and his IQ was not enough.
Later generations have a misunderstanding about Einstein, thinking that apart from the theory of relativity and the photoelectric effect, he seems to be an ordinary physicist with nothing to offer.
This statement is completely wrong. He also had the following achievements:
In 1905, he explained the nature of Brownian motion and gave a method to calculate Avogadro's constant.
In 1907, he solved the problem of specific heat of solids and became the founder of solid mechanics.
In 1916, the principle of laser was proposed, which provided a theoretical basis for the birth of laser in later generations.
In 1917, the static cosmology model was proposed, which became the beginning of later cosmology.
In 1924, he proposed Bose-Einstein condensation and was the pioneer of cold atom physics.
These results are actually at the senior level, but compared with the theory of relativity, of course they can only be considered small contributions.
Therefore, many people only know Einstein's theory of relativity and ignore his other achievements.
In fact, after a comparison, I was surprised to find out how awesome Einstein was in real history.
Relativity and quantum mechanics are equally profound and important theories.
The former was created by Einstein alone, while the latter was perfected by more than a dozen geniuses.
Let’s judge!
This is why in Ridgway's T-series classification, Einstein can be ranked alongside Newton and Maxwell, while others can only be moved down one level.
But no matter how you say it, it is the above-mentioned physics giants who jointly created the grand history of physics in the early 20th century.
However, it is only 1902, and history has already been changed by Li Qiwei.
He proposed the concept of the atomic nucleus and the atomic planet model nearly ten years in advance.
This will undoubtedly accelerate the development of physics as a whole, and even he himself doesn’t know how it will develop.
Li Qiwei is a witness and participant in this life, and may even be the leader in the end. How could he not be excited?
Currently, he holds the special theory of relativity and quantum theory, and can be called the founder and first patriarch of these two major theories.
As for publishing the general phase later, consider guiding Bohr, de Broglie and others to make achievements in quantum mechanics.
He can no longer imagine how future generations of physics history will evaluate himself.
Not to mention, he will also be present in future cosmic physics and atomic physics.
Even cross-border approaches, such as chemistry, biology, medicine, etc.
The more Li Qiwei thought about it, the more excited he became, and the more outrageous he thought about it, the more he almost laughed out loud.
This scene happened to be seen by Wilson who came to see him, "Bruce, what good things have you thought of again?"
Then he said mysteriously: "I heard about you Doctoral results, overturned Professor Thomson?"
Li Qiwei asked: "How do you know?"
Wilson grimaced: "The professor just came to me and said that both You and Rutherford have done groundbreaking work for the laboratory and asked me to work harder."
Li Qiwei: "Hahaha"< br>
Facing the ridicule of the genius, Wilson was naturally good-tempered and as steady as an old dog, and continued to ask: "Bruce, are you about to graduate with a Ph.D.?"
Li Qiwei thought for a while and said : "I should apply for doctoral defense at the end of this year or the beginning of next year."
He smiled slightly, it was time to get a doctorate title, otherwise I would be embarrassed to introduce myself when I go out in the future.
This chapter is still necessary. As you have seen, there is actually nearly 20 years between the next stage of the plot. If it is advanced, then those celebrities will not appear. If the original time is kept, then the ability to control the plot will be very high, so Lao Xu will carefully think about the subsequent story.
(End of this chapter)