Grand unified theory:
M theory is a theory proposed as the "ultimate theory of physics". It is hoped that a single theory can explain the essence and nature of all matter and energy. interactive relationship. It combines all superstring theories (the last five) and the eleven-dimensional supergravity theory. To fully understand it, Dr. Edward Witten believed that new mathematical tools needed to be invented.
From 1984 to 1985, the first revolution in string theory occurred, the core of which was the discovery of a unified theory of "abnormal freedom"; from 1994 to 1995, the second revolution in string theory occurred, which was both external and internal. , string theory evolved into M theory. Edward Witten, the leader of the second string revolution, was named the sixth most influential figure after World War II by the American "Life" magazine.
Another definition:
M theory was proposed by Lewis and Allen. Based on the survey of the true attitudes of managers and managed people from social and economic perspectives, a theory of comprehensive management definition is proposed.
[Edit this paragraph] What does the "M" in M ??theory mean?
Witten said: "M here can represent magic, mystery or membrane. ), it depends on what you like." Schwartz reminded everyone that M also represents matrix.
In the game of Go, there are only a few rules such as whether to go or not to go, and with the addition of black and white chess pieces, ever-changing games can be played. Similarly, modern science believes that nature is governed by a few rules and that there are an infinite variety of states and structures allowed by these governing laws. Any force not yet discovered will be extremely weak, or its effect will be severely limited. These effects are either limited to extremely short distances or only work on extremely special objects.
Scientists are very confident that they have discovered all the forces and missed nothing. But they lacked the same confidence when it came to describing the laws of these forces. The two pillars of 20th-century science—quantum mechanics and general relativity—turn out to be incompatible. General relativity violates the rules of quantum mechanics at the microscopic scale; black holes challenge the foundation of quantum mechanics itself at the other extreme scale. Faced with this dilemma, rather than saying that physics is no longer brilliant, it is better to say that this heralds a new revolution.
The unified electroweak theory of A. Salam and S. Weinberg simplifies the two laws describing the electromagnetic force and the weak force respectively into one law. The ultimate goal of M theory is to use a law to describe all known forces (electromagnetic force, weak force, strong force, gravity). Currently, the evidence in favor of M theory is increasing day by day, and exciting progress has been made. The sign of M theory's success lies in making quantum mechanics and general relativity compatible in a new theoretical framework.
Like string theory, the key concept of M theory is supersymmetry. The so-called supersymmetry refers to the symmetry between bosons and fermions. Bosons are named after S.N. Bose, a physicist at the University of Calcutta, India; fermions are named after E. Fermi, a physicist who proposed the Manhattan Project. Bosons have integer spin, while fermions have half-integer spin. Relativistic quantum theory predicts a connection between the spin of a particle and its statistical properties, a prediction that has been stunningly confirmed in nature.
In supersymmetric physics, all particles have their own supersymmetric partners. They have exactly the same quantum numbers (color, charge, baryon number, lepton number, etc.) as the original particles. The superpartner of a boson must be a fermion; the superpartner of a fermion must be a boson. Although firm evidence for the existence of the supersymmetric partner has yet to be found, theorists remain convinced of its existence.
They believe that because supersymmetry is broken spontaneously, the mass of the superpartner particle must be much greater than that of the original particle, so its existence cannot be detected in existing accelerators.
Local supersymmetry also provides new ways to incorporate gravity into a unified theory of physics. Einstein's general theory of relativity is derived based on certain requirements under the generalized space-time coordinate transformation. Under the supersymmetric space-time coordinate transformation, local supersymmetry predicts the existence of "supergravity". In the theory of supergravity, the gravitational interaction is transmitted by a boson (graviton) with a spin of 2; and the super partner of the graviton is a fermion (graviton) with a spin of 3/2. It delivers a short-range interaction.
[Edit this paragraph] Historical joke: Back to 11 dimensions
General relativity does not set an upper limit on the dimension of space and time, and the theory of gravity can be established on any Riemannian manifold. The theory of supergravity sets an upper limit for the dimensions of space and time—11 dimensions. What is even more fascinating is that it has been proven that 11 dimensions is not only the maximum dimension allowed by supergravity, but also the minimum dimension included in the isometry group SU(3)×SU(2)×U(1). The standard model describing the strong force, namely quantum chromodynamics, is a gauge theory based on the local symmetry group SU(3). Its quanta are called gluons, which act on an intrinsic quantum number called "color". The Weinberg-Salam model describing the weak force and electromagnetic force is based on the SU(2)×U(1) gauge theory. This normative group acts on "taste" rather than "color". It is not precise but breaks spontaneously. For these reasons, many physicists began to explore an 11-dimensional supergravity theory, hoping that this would be the unified theory they sought.
However, in the face of chirality, one of the pillars of gravity theory suddenly collapsed. Chirality 2 is an important feature of nature, and many natural objects have symmetry similar to that of the human left and right hands. The spin of a neutrino is always left-handed.
In the 1920s, the Polish T.Kaluza and the Swedish O.Klein discovered the mechanism for reducing high-dimensional space to observable 4-dimensional space-time. . If the 7-dimensional space in 11-dimensional supergravity is compact and its scale is 10-33 cm (so it is not detected), it will lead to SU(3)×SU(2) required by the standard model of particle physics. )×U(1) symmetry group. However, when space-time is compacted from 11 dimensions to 4 dimensions, chirality cannot be derived. By 1984, supergravity lost its position as the leading theory and was replaced by superstring theory. At that time, "To hell with the 11th dimension!" - this famous saying of M. Gell-Mann, the "father of quarks", expressed the disappointment of many physicists with the 11th dimension.
Since 1984, people have determined that 10-dimensional space-time is the best choice, and the string theory of 10-dimensional space-time has replaced the supergravity theory of 11-dimensional space-time. There have been five popular string theories, the differences lie in the number of unbroken supersymmetry charges and the gauge groups they carry. In 10-dimensional space-time, the smallest spinor has 16 real components. There are three conserved supercharges of string theory that correspond to this situation. They are type I, heterotic strings HE and HO. The remaining two string theories contain two spinor supercharges and are called type II strings. Among them, type IIA spinors have relative chirality, and type IIB spinors have the same chirality. There are two types of heterotic strings, HE and HO, with E8×E8 gauge group and SO(32) gauge group respectively. Type I strings also have the SO(32) gauge group, which is an open string, while the other four types of strings are closed strings. Importantly, they are both anomalously free, i.e. string theory provides a theory of gravity that is compatible with quantum mechanics. In these theories, HE strings can, at least in principle, explain the properties of all known particles and forces, including chirality.
However, string theory is by no means beautiful, and it can be challenged from at least four aspects.
First of all, people originally pursued string theory as a unified theory of physics, but its five different theories gave five different universes. If humans live in one of the universes, then the other four theories describe universe, and what kind of creatures live in it? Secondly, if particles are regarded as strings, why not regard them as membranes, or as p-dimensional objects—branes? Furthermore, regarding the experimental verification of string theory, the traditional particle accelerator method is obviously limited by both technology and funding. However, where are the new methods? Finally, the maximum dimension of space-time allowed by supersymmetry is 11 dimensions. Why does string theory stop abruptly when it only reaches 10 dimensions? Did the remaining dimension escape or hide?
History is really a joke. Ten years after people let 11 dimensions "go to hell", the second revolution in string theory began in 1994. Since then, five different string theories have been shown to be essentially equivalent and can be derived from M-theory in 11-dimensional space-time. After ten years of arduous toil, people have returned to the original dimension of space and time. Negation of negation is indeed a mysterious philosophy.
[Edit this paragraph] Duality and M theory
The 11-dimensional vacuum of M theory can be characterized by a single scale called the 11-dimensional Planck mass mP. If a spatial dimension in the 11-dimensional space-time is taken as a circle with radius R, it can be connected with type IIA string theory. Type IIA string theory has a dimensionless string coupling constant gs, which is determined by the value of the dilaton field Φ (a massless scalar field belonging to the type IIA supergravity multiplet). The square of the mass scale ms of type IIA gives the tension of the basic IIA string. The relationship between the parameters of the 11-dimensional and 10-dimensional IIA is (omitting the numerical factor 2π) ms2=RmP3, gs=Rms.
The perturbation analysis often used in IIA theory fixes ms and expands gs. It can be seen from the second relation that this is an expansion about R=0, which is why no 11-dimensional explanation is found in string perturbation theory. The radius R is a module determined by the value of a massless scalar field with a flat potential. If the value of this module is zero, it corresponds to the IIA theory; if it takes the value of infinity, it corresponds to the 11-dimensional theory.
The heterotic string HE has a similar connection with the 11-dimensional theory. The difference is that the compact space is no longer a circle, but a line segment. This compactification will produce two parallel 10-dimensional slices, each corresponding to an E8 gauge group. Gravitational fields exist within blocks. From the 11-dimensional space-time, it can be better explained why the adoption of the E8×E8 gauge group is the "abnormal freedom" of quantum mechanics.
As early as the beginning of this century, German female scholar A. Noether proved a famous law: symmetry corresponds to a certain physical conservation law. Electric charge, color charge, and other conserved charges can be regarded as Noether charges. The properties of certain particles remain unchanged under field deformation. Such a conservation law is called topological, and its conservation charges are topological charges. According to the traditional view, leptons and quarks are considered elementary particles, while solitons carrying topological charges such as monopoles are derived. Can we conjecture it upside down? That is to say, it is conjectured that the monopole carries Noether charge, while the electron carries topological charge? This conjecture is called the Montonen-Olive conjecture, and it brings unexpected surprises to physical calculations. An elementary particle with e charge is equivalent to a topological soliton of 1/e, and the charge of the particle corresponds to its interaction coupling strength. The coupling strength of quarks is strong, so it cannot be calculated by perturbation theory, but it can be calculated by dual theory with weak coupling strength.
A breakthrough in this regard was achieved by Indian physicist Ashoke Sen. He proved that in supersymmetric theory, there must be solitons with both electric and magnetic charges. When this conjecture was extended to string theory, it was called S-duality. S-duality is the duality between strong coupling and weak coupling, since the coupling strength corresponds to the value of the dilaton field Φ. The heterotic string HO and the type I string can be connected through their respective dilation subfields, that is, Φ(I)+Φ(HO)=0.
Weak HO coupling corresponds to Φ(HO)=-∞, while strong HO coupling corresponds to Φ(HO)=+∞. It can be seen that heterotic strings are non-perturbative excited states of type I strings. In this way, S-duality explains a long-standing puzzling issue: HO strings and I-type strings have the same supersymmetry charge and gauge group SO (32), but have very different properties.
In string theory, there is also a duality between large and small compact volumes, called T-duality. For example, the compactification of IIA theory on a circle with radius RA and the compactification of IIB theory on another circle with radius RB are equivalent and have the relationship RB=(ms2RA)- 1.
Thus, when modulus RA changes from infinity to zero, RB changes from zero to infinity, which gives the connection between IIA and IIB. Although the technical details of the connection between the two types of hybrid strings are different, the essence is the same.
String theory also has a symmetry of orientation reversal. If a directional string is projected, two different results will be obtained: a twisted non-directional open string and an undistorted non-directional closed string. This is the connection between type IIB strings and type I strings. In the language of M theory, this result is said: open strings are derivatives of Dirichlet embryos.
[Edit this paragraph] Classification and duality of p embryos
As we all know, vector particles with mass have 3 polarization states, while massless photons only have 2 polarization states. . The massless state can be regarded as the critical state of the massed state. In the Poincaré symmetry of 4-dimensional space-time, the photon state is described by a small group representation. Small group representation is also called short representation. This algebraic structure can be extended to the 11-dimensional supersymmetry theory. Critical mass also reappears in M-theory. According to Noether's theorem, the conservation of energy and momentum is a corollary of the translational symmetry of space-time. The anticommutator of a supersymmetric charge is a linear combination of energy and momentum, which is the algebraic basis of supergravity. However, the anti-changer of two different supersymmetric charges can generate new charges. This charge is called the central charge Q. There is also a short representation for superalgebras with central charges, which will be closely related to the non-perturbative structure of M-theory.
For particle states with central charges, the algebraic structure implies the physical relationship m≥|Q|, that is, the mass will be greater than the absolute value of the central charge. If the particle state is a short representation, this relationship takes the critical case m=|Q|, which is usually called the BPS state. The original form of this property was discovered by former Soviet scholar E.B. Bogomol'nyi and American scholars M.K. Prasad and C.M. Sommerfield when they studied monopoles in gauge fields. .
If the BPS state concept is applied to the p embryo, then the central charge is described by a p rank tensor, and the BPS condition becomes that the unit volume mass of the p embryo is equal to the charge density. The p-embryo in the BPS state would be a solution to a low-energy efficient theory that preserves some supersymmetry. Both type II strings and 11-dimensional supergravity contain two types of BPS state p embryos, one is called electric and the other is called magnetic, and they both retain half of the supersymmetry.
In 10-dimensional string theory, according to the dependence of string tension Tp and string coupling constant gs, p embryos can be divided into three categories. When Tp is independent of gs, and the relationship with the string mass parameter is Tp∽(ms)p+1, the embryo is called a basic p embryo; this situation only occurs when p=1, so it is also called a basic string; this is also is the only solution under weak coupling, so it is a string for which only perturbations can be used. When the string tension Tp∽(ms)p+1/gs2, the embryo is called a soliton p embryo; in fact, this only occurs when p=5, which is the magnetic dual of the basic string and is recorded as NS5 embryo. When Tp∽(ms)p+1/gs, the embryo is called Dirichlet p embryo, recorded as Dp embryo, and its properties are between basic strings and solitons. Through magnetic duality, the Dp embryo will be linked to the Dp′ embryo, where p+p′=6.
In the 11-dimensional space-time, there are two types of p-embryos: one is the M2 embryo, which was once named the supermembrane, and the other is the 5-embryo called the M5 embryo. They are electromagnetic pairs with each other. The 11-dimensional theory has only one characteristic parameter mP, and its relationship with the string tension Tp is Tp∽(mP)p+1.
Type IIA theory can be derived by circumferentially compacting the 11-dimensional theory through 1-dimensional space. So, what changes will the p-embryo undergo during this compaction process? The spatial dimension of the p-embryo may or may not occupy the compact dimension. If it is occupied, the M2 embryo will curl into a basic chord, and the M5 embryo will curl into a D4 embryo; if it is not occupied, the M2 embryo will become a D4 embryo, and M5 will become an NS5 embryo.
[Edit this paragraph] Will it set off a cosmological storm?
At that time, many physicists abandoned 11-dimensional supergravity and ruthlessly let it go to hell. This is because Witten and others believe that chirality cannot be derived when compacting 11 dimensions into 4 dimensions. Ten years later, Witten denied himself again. This denial was the expression of Witten's powerful and profound philosophical atmosphere. In fact, the external world that exists independently of human beings is like a huge and eternal mystery. Gazing and contemplating this world is like seeking liberation, which attracts every physicist with a philosophical temperament.
Witten and Peter Horava discovered that the origin of chirality can be found from the 11-dimensional M theory. They contracted a space dimension in M ??theory into a line segment and obtained two 10-dimensional space-times connected by this line segment. Particles and strings exist only in two parallel space-times at both ends of the line segment, and they are connected to each other through gravity. Physicists speculate that all visible matter in the universe is located in one of them, while the dark matter that troubles physicists is in another parallel space and time, and matter and dark matter are connected only by gravity. In this way, we can neatly explain why there is invisible mass in the universe.
This image has extremely important physical significance and can be used to test M theory. In the 1970s, physicists realized that the coupling strength of all interactions changes with energy, that is, the coupling constant is no longer a constant, but a function of energy, and gave it a vivid name - the running coupling constant. In the 1990s, physicists also discovered that in the supersymmetric grand unified theory, the coupling strengths of the electromagnetic force, the weak force, and the strong force converge at a point where the energy scale E is approximately 1016 gigaelectronvolts. Physicists applauded this success, and some romantic critics even believed that supersymmetry had achieved final victory and no longer had to wait for the 2005 test experiment at the LHC collider.
However, only three of the four fundamental interactions of the universe are unified here, and one is gravity. How will we deal with the gravity that humans first understood? What is inspiring is that the coupling strength of the above three unified forces is similar to the dimensionless quantity GE2 (G is Newton's gravitational constant), but not equal. In the Witten-Holava scheme, the dimensions of the line segments can be chosen so that the four known forces converge together on the same energy scale E. This means that the quantum effects of gravity will operate on a scale much lower than the Planck energy scale (E≈1016 gigaelectronvolts), which will undoubtedly have a comprehensive impact on cosmology. If cosmologists looked out their windows, they might be alerted to the brewing storm, but most continue to indulge in the celebration of the Standard Model of the Universe.
[Edit this paragraph] Black embryo: the outstanding achievement of M theory
When other types of forces do not exist, all systems affected by gravity will collapse into black holes. The reason why the earth is not crushed by its own weight is because the material that makes it is very hard, and this hardness comes from electromagnetic force. Similarly, the reason why the sun did not collapse is only because the nuclear reaction inside the sun produced a huge outward force. If the Earth and Sun lost these forces, they would shrink faster and faster in just a few minutes. As they shrink, gravity increases and the rate of contraction increases, engulfing them in the rising curvature of space-time and turning them into black holes. When looking at a black hole from the outside, time seems to have stopped there and no further changes are visible. What a black hole represents is the final equilibrium state of a system affected by gravity, which is equivalent to the maximum entropy. Although general quantum gravity is still unclear, Stephen Hawking used quantum theory to successfully propose an entropy formula for black holes. This fact is sometimes called the black hole paradox.
Dutch theoretical physicist G.t'Hooft, who solved the problem of gauge field quantization in his twenties, once asked string scholars why string theory failed to solve the black hole problem. Question. At that time, people did not understand whether this was a challenge or an encouragement. However, as string theory evolved into M-theory, all doubts quickly dissipated. Hooft, a genius with a very keen sense of physics, heard the thunder when the rain was about to come, but he could not foresee what kind of storm was coming!
Under certain circumstances, a Dp embryo can be interpreted as a black hole, or more appropriately a black embryo, that is, an object from which no matter (including light) can escape. Therefore, the open string can be regarded as a closed string partially hidden in the black embryo. Black holes can be regarded as composed of seven compact-dimensional black embryos, so M theory will provide a way to solve the black hole paradox. Hawking believes that black holes are not completely black and can radiate energy. Black holes have entropy, which is the degree of disorder of a system measured by the number of quantum states. Before M theory, people were at a loss as to how to count the number of quantum states in black holes. Andrew Strominger and Cumrun Vafa used the Dp embryo method to calculate the number of quantum states in the black embryo. They found that the calculated entropy was exactly what Hawking predicted. This is undoubtedly another outstanding achievement of M theory.
There are thousands of ways to compact 10-dimensional string theory into 4 dimensions, and different ways produce different operating mechanisms in the 4-dimensional world. Therefore, people who do not believe in strings believe that this is not a prediction at all. However, in M ??theory, black embryos are expected to solve this problem. It has been proven that when the black embryo shrinks around a hole, the mass of the black embryo disappears. This property will have a wonderful impact on space-time itself. It will change the laws of classical topology and cause the topology of space-time to change. A space-time with several holes can be imagined as a piece of Shanghai breakfast - bee cake. Under the influence of the black embryo, it turned into another piece of bee cake, that is, into another space-time with a different number of holes. Using this method, all different time and space can be connected. In this way, the problem of string tightness can be easily solved. M theory will eventually choose a stable space-time according to a certain extreme value principle, and strings will survive in this space-time. The next step is that the vibrating string will produce particles and forces known to humans, that is, the real world in which humans live.
[Edit this paragraph] is still an open question
Although M theory has achieved numerous results, there are various signs that what has been glimpsed are just some "snow and mud claws" , the deepest mysteries have yet to be revealed, and what is the true face of M theory remains an open question. Although the success of M theory has freed string theorists from their past predicaments, they will surely encourage themselves by saying, "Do you remember the bumpy past? The road was long and people were stranded, and the donkeys neighed."3, hoping to discover new discoveries in the next few years. The true face of M theory.
American scholar Leonard Susskind and others made a new attempt. They called M theory matrix theory (the word matrix in English also starts with M). Try to give a strict definition of M-theory. The basis of matrix theory is an infinite number of zero embryos (i.e., particles). The coordinates of these particles (i.e., the positions in space and time) are no longer ordinary numbers, but matrices that cannot be commutated with each other. In matrix theory, spacetime itself becomes a fuzzy concept, an approach that greatly excites physicists. Schwartz called on everyone to pay attention to these studies, and pointed out that matrix theory contains an important unresolved problem: "When multiple space compact dimensions appear, using torus Tn compactification in matrix theory will encounter difficulties, Maybe better compactification methods will be found, otherwise new research will be necessary."
Einstein said: "The most incomprehensible thing about the world is that the world is understandable. "Today, the most incomprehensible thing about M theory is that it has actually taken a big step forward in understanding the world.
[Edit this paragraph] Hawking explains "M Theory"
Professor Hawking, a master of science, gave a popular science report on the theme "The New World of Branes" at the Beijing International Convention Center. Different from yesterday's International String Theory Conference, Professor Hawking used his special way of clicking on the computer this afternoon to explain his "theory of celestial evolution" to the Beijing public in more "public" and "popular" language. M-theory".
When Professor Hawking appeared in the lecture hall, the audience stood up to welcome this great man in a wheelchair, and warm applause rang out three times in succession. The report begins with the playful voice of a speech synthesizer. During the course of nearly two hours, he used the controller in his hand to give a report, and each vivid picture brought the audience into a magical world. During the nearly two-hour report, the audience was completely silent. Only a few small humorous moments in the middle made the audience burst into laughter.
Simple things need to be complicated to impress people. On the contrary, Hawking used simple language to explain the most profound theories in the world today. Our eyes only have three dimensions, but Hawking wants to explain the ten-dimensional space in simple language. Hawking's "M Theory" puts the audience on a platform that is usually unimaginable. The report explains "M Theory" in a simple and easy-to-understand way. According to the reporter, if you read Hawking's "A Brief History of Time", you may understand more about "genius" in his wonderful speech. However, it is easiest for geniuses to become stars, and the audience seems to have become "star followers".
Due to his thorough preparation, Professor Hawking's report was quite successful. Professor Hawking only needed to click his fingers to complete the entire reporting process. Professor Hawking's report ended at about 5:10, and he hurriedly left the conference center. He did not accept questions from reporters during the report and did not accept interviews with reporters after the report.
After the scientific master Professor Hawking came to China, "Hawking Fever" quickly swept across China. Hawking has been fighting the disease for more than 30 years. Although he now only has three fingers under his control, he doesn't like to be regarded as a disabled person. Although his body was restrained, Hawking's brain never stopped thinking about the vast universe.
"String theory" is the boldest theoretical hypothesis in physics today. It unifies the two basic theories of general relativity and quantum mechanics for the first time, and is expected to solve some century-old problems that have long plagued the physics community, such as the nature of black holes and the origin of the universe. If this theory is confirmed by experiments, it will fundamentally change people's understanding of the structure of matter, space and time.
A basic point of view of "string theory" is that the basic units of nature are not particles like electrons, photons and quarks. These things that look like basic particles are actually very small strings. A closed circle (called a closed string or a closed string), and the different vibrations and motions of the closed string give these different elementary particles. Recently, people's understanding of the structure of string theory has made rapid progress, and many new components ("branes") in string theory have been discovered. Now people usually refer to string theory and these newly introduced theories as "brane theory".
For the last 30 years of his life, Einstein had been searching for a theory? A theory that could describe all the forces of nature within a single, all-encompassing mathematical framework. Although Einstein returned empty-handed, today, some physicists believe they have discovered a theory that can stitch together this knowledge, which is superstring theory. This is the theme of the "Beijing International String Theory Conference" that Hawking came to attend. .
These theories are very difficult to understand for the general public with only ordinary knowledge. For example, the objects we see with the naked eye are three-dimensional, and if we add the dimension of time, they are four-dimensional. But "brane theory" reveals the 10th-dimensional space direction of string theory, because the maximum dimension of the theory is 11 dimensions. And it is thought that we may now be able to detect those extra dimensions. So what exactly is going on? Perhaps only Hawking can explain all this in a popular way, and the answer may lie in his popular science report.
Hawking’s life and achievements
Hawking’s life is very legendary.
In terms of scientific achievements, he is one of the most outstanding scientists of all time.
Hawking is the most important contemporary general relativity theorist and cosmologist. In the 1970s, he and Penrose proved the famous singularity theorem, and they both won the Wolf Prize in Physics in 1988.
After 1980, his interest turned to quantum cosmology. He began writing "A Brief History of Time" in 1982. Hawking believed that his lifetime contribution was to prove the inevitability of black holes and the Big Bang singularity in the framework of classical physics. Black holes become larger and larger; but in the framework of quantum physics, he pointed out that black holes become larger and larger due to radiation. Becoming smaller and smaller, the singularity of the Big Bang is not only smoothed out by quantum effects, but the entire universe began here.
Since its first publication in April 1988, the book has been translated into 30 languages ??and sold approximately 5.5 million copies.
[Edit this paragraph] "PBS String Theory and M Theory"
Chinese name: PBS String Theory and M Theory
English name: String Theory And M Theory
Resource type: DVDRip
Release date: 2005
Region: United States
Language: English
Resource Category: Information/Documentary
Introduction:
String theory is a theory in theoretical physics. The physical model in the theory believes that the most basic unit that makes up all matter is a small "energy string". Basic particles as large as interstellar galaxies and as small as electrons, protons, and quarks are all composed of this "energy" that occupies a two-dimensional space. "line". In Chinese translation, it is usually translated as "string" or "string".
The particle theory established earlier believes that all matter is composed of "point" particles occupying only one dimensional space. It is also a widely accepted physical model and a very successful explanation. and predict quite a few physical phenomena and problems, but the "particle model" on which this theory is based encounters some unexplainable problems. In comparison, "string theory" is based on the "wave model" and therefore can avoid the problems encountered by the former theory. The deeper string theory theory not only describes "string"-like objects, but also includes point-like and film-like objects, higher-dimensional spaces, and even parallel universes. It is worth noting that string theory has not yet been able to make accurate predictions that can be experimentally verified. This will be explained below.
[Edit this paragraph] Evaluation of Superstring Theory and M Theory
The evaluation of Superstring Theory and M Theory is far beyond human imagination
General Theory of Relativity Unification with quantum mechanics is still far away
No contemporary scientist can draw a perfect Hubble diagram. The R--W metric of standard cosmology is created out of thin air and Hubble's law is hard inserted, so Hubble often teaches There is no generally accepted accurate value for the value of H. Data analysis of cosmic observations is what everyone needs. Papers by top astronomy scholars on international websites do not have accurate H values. Physical and chemical events on galaxies with redshifts greater than 1 cannot be accurately reflected. In particular, Qiu Chengtong, director of China's Morningside Mathematics Center, boasted on the center's website that string theory is close to solving the ultimate cause of the origin of the universe. But string theory is just the derivation of mathematicians. They don't even know the cause of the red shift of the universe, and they can't complete the Hubble diagram. Anyone's theory of the origin of the universe is a fallacy. Therefore, the unification of gravity and the four microscopic forces is indeed far away. Anyone who wants to become a true cosmologist must not find cosmology from Einstein's gravitational field equations, but must analyze redshift data and find the relationship between distance and redshift. Without solving Einstein's gravitational field equations, he must directly Now the spherical symmetry of the gravity metric is found and a perfect Hubble diagram is drawn. Any ordinary student who has studied general relativity can understand the derived simple universe metric. At this point you will realize how ridiculous the cosmology is.