String Theory: Why?

For more than 30 years, string theory has been a topic of discussion in the world of theoretical physics, and people in other branches of science respect it. This is because Einstein's unified field theory is the most successful of all attempts to formulate it. Maybe that's why students who are so good at physics are also interested in string theory. Does it really have any real achievements, or are all its achievements ‘media creation’? To find the answer to this question objectively, we need to look at the origin of this theory.

Although we now consider string theory to be an attempt at quantum interpretation of the gravitational ball, it began as a model for a strong nuclear ball. Scientists found in the 1950's that the reaction of pi masons with protons or neutrons (I wrote a little about the interaction of these particles in earlier issues of scientific thought) gave rise to many resonance particles, which are very transient. It was also seen that with the increase in the value of energy, such new resonant particles are being discovered. As if there is no end to it. It is said that Nobel laureate scientist Willis Lamb jokingly offered a লার 10,000 fine instead of awarding the Nobel Prize for discovering new particles. However, the existence of these resonant particles can be explained by the currently established quark design, but at that time string theory emerged to explain these growing resonant particles. A single string has many frequencies (as we see in guitars or any other instrument). And the number of these different frequencies is infinite. Scientists also wanted to explain the particles participating in this (strong) central interaction (what we call Hadron) as a different excited state of a basic wire or yarn. This theory has only one parameter. And that is the tension of the wire. To explain the nature of a strong centrifugal ball, the value of this tension needs to be 109 electronvolts.

In general quantum field theory, the fundamental particles we deal with form a spacetime line in the evolution of time, where we call it the worldline.

Strings can be of two types: open or closed. Just as the evolution of a particle gives a line, so the evolution of a string will give a two-dimensional surface. For open strings it will be like a sheet, and for closed strings the surface will be like a tube.

But this explanation worked in some cases, but in one place it fell on its face. According to the laws of quantum mechanics, a phase was found between the different phases of this wire, which would appear as a massless particle (e.g., light particle, photon), but its spin would be quantum number 2. No such hadron is seen in the laboratory. For this reason, those who were trying to explain the strong central force through strings or strings, got a little depressed. At the same time, due to the prevalence of the concept of quark, many people stopped working on this style of string theory, which is now known as the Undhas Tvangrahadhapab model. Even then, some dedicated scientists continue to work on this theory. In 1974, John Schwartz and Joel Shark Mill (and separately Tamiaki Yoneya) showed that if the tension of a wire is 1019 watts instead of 109 watts, this unusual massless particle with a spin quantum number 2 can be considered as a quantum particle of gravitational graviton. Because, it adheres to Einstein's equation of general relativity. Their discovery not only saved string theory from certain immortality, but also led string theory to be considered as the claimant of the correct quantum theory of gravity. In addition, scientists have found that the number of spatial dimensions (theoretically) needs to be 26 or 10 to formulate a proper quantum theory of strings. While this may seem like an error, it is actually a curse. To understand this we have to go back to 1919. At this point, Theodore Kaluza showed that if Einstein's theory, written for the five-dimensional world, is projected into the four-dimensional world, Maxwell's electromagnetic equations are also hidden in it. It is a fruitful step towards formulating integrated field theory. This means that string theory is formulated in a world of more than four dimensions, so this theory explains the presence of gravity as well as other fundamental balls in our world.

Meanwhile, the basic particles we see can be divided into two classes শ্রেণ bosons and fermions মান according to the value of their spin quantum numbers. The string theory we've been talking about so far only predicts boson particles. However, this does not explain any of the fermion particles we see. This is why such a string theory is called Bosnian string theory. There are several flaws in this theory, two of which are more eye-catching. First, the mass of a particle must be a real quantity. Because of this the square of mass can never be a negative number. If this is the case the lowest power condition of the system will not be stable. This is easily illustrated by the following figure:

The figure on the left has a minimum value of energy at which the system will settle, but something like that is not possible in the figure on the right. In this case, there will be no minimum power level in the system. In that case, the system will continue to emit energy automatically, which does not match our experience. In Bosnian string theory, the right condition occurs. And the second problem is that for this theory, the dimension of spacetime has to be 28, which is very different from the four-dimensional spacetime we have seen. The first of these two errors is more contagious.

To fix this error, we have to work with superstring theory instead of Bosnian strings. The adjective ‘super’ is used, because here the supermator is used. Super-symmetry is a symmetry where all quantum numbers remain the same except for the spin of boson and fermion particles. The total power of any system with super-symmetry can never be negative. For this reason the problem of Bosnian string theory is not created in the case of superstring. Another relatively good aspect of the superstring theory is that for this we need to have a Jake 10 dimension, which is 16 dimensions less than the 28 dimension of the Bosnian string. In addition, boson particles as well as fermion particles are formed in the vibration of the superstring, which is why the superstring is more suitable than the bosonian string to explain the world we see.

But no matter how striking and interesting the theoretical scientists may come up with, the hardest part of examining a theory is its results. There is a desire to discuss in the next issue of Scientific Thought what the verdict would be if string theory is put to the test.