Theory of relativity

Quantum theory (including quantum mechanics, quantum field theory and quantum statistics)

high-energy physics

Subatomic particles (see detailed classification)

astrophysics

Nuclear physics and radiology

Condensed matter physics and related disciplines;

semiconductor

materials science

computational physics

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The development direction of physics at the turn of the century

This paper reviews the history of physics development and discusses the development direction of physics in 2 1 century. It is believed that physics will continue to develop in three directions in the 2 1 century: (1) deepening in the microscopic direction; (2) expand in the macro direction; (3) Deeply explore the relationship between different levels and further develop nonlinear science. Perhaps we should explore the breakthrough of modern physical revolution from two aspects: (1) discovering other forces in the objective world except the four known forces; (2) Considering the imperfection of the theoretical basis of relativity and quantum mechanics, we redefine time and space and establish a new theory.

The 20th century is coming, and the 21st century is coming. The twentieth century is a glorious century, and it is the century with the fastest development of human society, science and technology and physics. In this century, there has been a revolution in physics, which has established relative stationery and quantum mechanics and completed the transformation from classical physics to modern physics. Since the 1920s and 1930s, modern physics has further developed in depth and breadth, and a series of new interdisciplinary and marginal disciplines have emerged. Humans have a deeper understanding of the laws of the material world, physics theory has reached a new height, and modern physics has reached a mature stage.

At the turn of the century, people naturally want to look forward to the development prospect of physics in 2 1 century and explore the future development direction of physics. I want to talk about some of my views and opinions on this issue. First, let's review the development of physics at the turn of the last century. Comparing the present situation with that of a hundred years ago is very helpful to explore the development direction of physics in 2 1 century.

I. Historical review

1At the end of the 9th century and the beginning of the 20th century, all branches of classical physics developed to a perfect and mature stage. With the establishment of thermodynamics, statistical mechanics and Maxwell's electromagnetic field theory, classical physics reached its peak. At that time, people systematically drew a clear and complete picture of the physical world, which could explain almost all the observed physical phenomena perfectly. Due to the great achievements of classical physics, many physicists at that time had the idea that the building of physics had been built, the development of physics had been basically completed, and people's interpretation of the physical world had come to an end. Some basic and principled problems in physics have been solved, and the only thing left is to be more accurate, that is, to make some supplements and corrections in some details so that the constants in known formulas can be measured more accurately.

However, at the end of 19 and the beginning of the 20th century, physicists celebrated the completion of the physics building, and at the same time, scientific experiments discovered many facts that classical physics could not explain. The first is the three major discoveries of physics at the turn of the century: the discovery of electrons, X-rays and radioactive phenomena. Secondly, there are two "dark clouds" in the clear sky of Wan Li's classical physics: the "zero result" of ether drift and the "ultraviolet disaster" of blackbody radiation. Others began to discuss the creation of the universe, thinking that the universe is from scratch and will continue to develop in this direction in the future. Fundamentally speaking, the continuous development of modern cosmology depends on new observation results in more distant places in the vast universe, which requires human beings to create space astronomical telescopes with much superior performance than Hubble telescope, which is a very arduous task.

Personally, I don't believe in the creation theory of the universe put forward in recent years, and think that the "Big Bang" theory is only an approximate description of the universe. Because the current cosmology only studies the "universe" within the range we can observe, and I believe that the universe is infinite, and there are countless "universes" outside our "universe". These universes are not unrelated and isolated, but interact with each other. Modern cosmology only studies our "universe", of course, it can only get approximate results, and it is even more wrong to extend their extension to the "universe" to create an early and distant future.

3) Explore the relationship between different levels.

This is the main content of statistical physics research. Great achievements have been made in this field in the 20th century. First, great progress has been made in non-equilibrium statistical physics, then the theory of "dissipative structure", synergy theory and catastrophe theory have been established, and then chaos theory and fractal theory have been developed one after another. In recent years, these branches have been included in the category of nonlinear science. It is believed that the development of nonlinear science will have broad prospects in 2 1 century.

The above development of physics is still within the framework of the existing basic theories of modern physics. How should the basic theory of physics develop in the next century? Some physicists are pursuing "super unified theory". In this regard, at first, talented scientists such as Einstein and Heisenberg tried to explore the "unified field theory"; Until 1967 and 1968, Weinberg in the United States and Salam in Pakistan put forward the "electric weakness theory" to unify electromagnetic force and weak force; At present, some physicists are exploring the powerful "grand unification theory" and the "super unification theory" that unifies all four forces by gravity. Whether their exploration can be successful is still inconclusive.

Einstein's exploration of "unified field theory" is based on his thought of "the unity of the physical world" [4], but he tried hard for 30 years and finally failed. I have a different view on this. According to the basic principle of dialectical materialism, I think that "the material world is both unified and diverse". Not to mention the success of pursuing the "super-unified theory", even if this theory is completed, it is not the end of the development of physics. Because "in the absolute overall development of the universe, the development of each specific process is relative, so in the long river of absolute truth, people's understanding of the specific process of each specific development stage is only relative truth." The sum of countless relative truths is the absolute truth. ""People's knowledge of truth in practice will never end. " [5]

How will the revolution of modern physics happen? I think there may be two aspects worth investigating:

1) There may be more than four forces in the objective world. What are the fifth and sixth forces? Now we don't know. My intuition is that the fifth force first discovered in the future may exist in life phenomena. After matter constitutes a living body, its movement and change are really mysterious, and there are too many problems we don't know. Our understanding of life science today is just like that of people in Aristotle's time, so it is very possible to make a breakthrough in this respect. In my opinion, the intersection of physics research and life science is one of the development directions of physics in 2 1 century, and the development of nonlinear science related to it is the most complicated research.

2) Modern physics theory is only relative truth, not absolute truth. We should explore the breakthrough of modern physics revolution from the imperfection of the theoretical basis of modern physics, and I will introduce my views in the next section.

3. Is the theoretical basis of modern physics perfect?

Relativity and quantum mechanics are two pillars of modern physics. Are the theoretical foundations of these two pillars perfect?

And then what? Let's think about this problem.

1) Reflections on Relativity

At that time, Einstein founded the special theory of relativity [1] by thinking about the nature of light speed and time. Today, when we explore the breakthrough of modern physics revolution, we should also start with rethinking the concept of time and space. Einstein's special theory of relativity was founded from the simultaneous occurrence of two "events" in different places in the inertial system [4]. He stipulated that "simultaneity" was defined by correcting clocks in two different places with optical signals, which naturally led to Lorentz transformation and further led to a four-dimensional space-time (X, Y, Z, ict)(c is the speed of light). Why do you love to propose to correct the clock with optical signals instead of other signals because of labor protection considerations? He didn't explain the problem in his paper. In fact, it has profound meaning.

Time and space are manifestations of material movement. Without physical movement, we can't talk about time and space. When defining time and space, we should explain what time and space are about. Modern physics thinks that the function of distance does not exist, and the "event" at A must be transmitted through a certain field, which takes some time. The definition of time and space is closely related to this transmission speed. If this field is an electromagnetic field, then the speed of electromagnetic interaction is the speed of light. Therefore, the space-time defined by Einstein is actually about the space-time of matter motion caused by electromagnetic interaction, which is suitable for describing this motion.

Einstein applied his definition of time to all material movements, which actually implied the hypothesis that the propagation speed of gravitational interaction is also the speed of light C, but does gravitational interaction also travel at the speed of light? Let the transfer speed of gravitational interaction be c'. So far, there is no experimental fact that C' is equal to C. Einstein actually assumed c=c because of his worldview of "the unity of the material world". I hold the view that "the material world is both unified and diverse", and the strength of electromagnetic force and gravity is too different in order of magnitude, so I believe that c' is not necessarily equal to c, and the four-dimensional space-time (x, y, z, ict) of material motion caused by electromagnetic force is different from that of gravity (x', y', z', ic't'). If the research problem only involves one kind of interaction, then the form of the motion equation established according to the current theory remains unchanged. For example, the form of Einstein's gravitational field equation remains unchanged, but the constant c is changed to c'. If the research problem involves two kinds of interactions, it is necessary to establish a new theory. However, first of all, it is necessary to judge whether C' and C are equal through experimental facts; If they are not equal, you need to export the value of c'.

I began to form the above viewpoint more than twenty years ago. At that time, measuring gravitational waves was a hot spot of concern. I have high hopes for those experiments, hoping to calculate whether C' is equal to C from the experimental results. Unfortunately, after a long period of efforts, the gravitational wave experiment did not get a positive result, and then the work cooled down. The gravitational wave predicted according to patriotic Stan theory is very weak. If such a weak gravitational wave can be detected under the measurement sensitivity and accuracy that can be achieved by modern experimental technology, the negative results of long-term experiments seem to imply the deficiency of causality stein theory. We should consider the problem from the perspective that C' is not necessarily equal to C. If C' and C are very different, it may be concluded that the intensity of gravitational waves is much weaker than predicted according to Einstein's labor protection theory.

Weak force and strong force are essentially different from gravity and electromagnetic force. The first two are short-range troops, and the last two are long-range troops. Different interactions are realized by transferring different mediator particles. The transmitter of gravitational interaction is graviton; The emitter of electromagnetic interaction is photon; The emitter of weak interaction is gauge particle (except photon); The transmitter of strong interaction is meson. The rest mass of gravitons and photons is zero. According to Einstein's theory, the propagation speed of gravitational interaction and electromagnetic interaction is the speed of light. Moreover, it is related to the static mass and energy of the transferred particles, so its transfer speed is changing.

When studying the motion of matter caused by weak or strong interaction, should we use weak or strong signals instead of light signals to define the "simultaneity" of two "events" in different places in the inertial system? As a layman in nuclear physics and particle physics, I don't want to answer this question rashly. If the light signal is to be replaced by weak force or strong signal, then the time and space of matter motion caused by weak force or strong force, the time and space of motion caused by electromagnetic force (x, y, z, ict) and the time and space of motion caused by gravity (x', y', z', ic't') are discussed.

There is a big difference. Let the propagation speed of weak interaction or strong interaction be c'', and c'' is not a constant, but a variable, then the time and space of motion caused by weak interaction or strong interaction are (x'', y'', z'', IC' t'', time t'', space (x'', y'', z'''. However, it is likely that the problem should be considered as follows: with regard to the motion space-time caused by weak force, the speed c 1 of gauge particles with zero rest mass should be used instead of the speed c in the definition. Because the "electric weak theory" unifies the weak force and electromagnetic force, it is possible that c 1=c, and the time and space of the motion caused by weak force and the motion caused by electromagnetic force are the same, both of which are (x, y, z, ict). As for the time and space caused by strong force, in the definition, the velocity c″ (there is no meson with zero static mass in theory) should be used instead of the velocity c″, which may not be equal to c, so the time and space (x″, y″, z″, Ic″, t″) caused by strong force is different from (x, y, z, ict). No matter which of the above two considerations is right, the time and space of the whole material world will be multidimensional time and space higher than four dimensions. For the motion of matter caused by short-range force (or just strong force), if space-time has new meaning, it is necessary to establish new theories, namely, new quantum field theory, new nuclear physics and new particle physics. If the problem studied involves both long-range force and short-range force (especially strong force), it is even more necessary to establish a new theory.

1) Reflections on Quantum Mechanics

When developing from quantum mechanics to quantum field theory, we encountered "divergence difficulty" [6]. During the period of 1946- 1949, Ichiro Asanaga, Feynman and Schwinge put forward the method of "reorganization", which overcame the "divergence difficulty". However, there are still logical defects in the theory of renormalization, and this difficulty has not been completely overcome. One of the basic reasons for "divergence difficulty" is that the "inherent" energy (static energy) of particles is calculated together with the kinetic energy and interaction energy [6], which is different from the de Broglie wave when υ=0.

Now I am in a dilemma: if we adopt the traditional de Broglie relationship, we have to accept the unreasonable de Broglie wave singularity; If we adopt the modified de Broglie relation, we must face the difficult problem of making the new theory satisfy the relativistic covariance. Are there any other ways to solve the problem? I think this problem may also be related to the definition of time and space. In the present theory of quantum mechanics, the definition of timeless man is still the definition of determinism, and the uncertainty principle is a basic law of the micro-world, so time and space are not strictly determined, and the essence of determinism in time and space is no longer applicable. When the interval between time and space is small, the concepts of "before" and "after" describing the order of things lose their meaning. In addition, when redefining time and space, we should also consider the categories of related material movements. Fuzzy mathematics has developed quite well, and it may be worth a try to apply this mathematical tool to the definition of time and space in the microscopic world.

1)2 1 century, physics will continue to develop in three directions (1) and deepen in the microscopic direction; (2) expand in the macro direction; (3) Deeply explore the relationship between different levels and further develop nonlinear science.

2) Maybe we should control the breakthrough of modern physics revolution from two aspects. (1) Discover other forces in the objective world except the four known forces; (2) Considering the theoretical basis of relativity and quantum mechanics, redefine time and space and establish a new theory.

3) Because there is no "crisis" in modern physics, the conditions for the revolution of modern physics may not be mature at present. The development and revolution of physics depend on obtaining new results in physical experiments and observing the objective material world. Experiment and observation are important quantitative means to develop physics, which is our primary concern. However, the development of science and physics has its own logic, and the thinking that conforms to objective laws and has insight is also a key.

My point of view is different. It may not be true insight, or it may be considered unconventional and counterintuitive by some people. However, I hope that these views can play a role in attracting jade and lead to a large number of insightful "jade". When ideas that do not conform to the current "convention" and "common sense" are in full bloom in the physics garden, we will usher in a more brilliant tomorrow for physics!