The battle for string theory

In the eyes of the general public, science is portrayed as a rational, orderly and objective occupation, and the scientists as restrained professionals, whose whole goal is to expand the boundaries of knowledge. The reality on the front of science is very far from this image, and string theory is an excellent example of this 

Barak Cole, Galileo

In the eyes of the general public, science is portrayed as a rational, orderly and objective occupation, and the scientists as restrained professionals, whose whole goal is to expand the boundaries of knowledge. Back in school we learn that unlike the humanities subjects, "for every scientific question there is a single correct answer". Although there is a degree of truth in this as long as it is about long-standing scientific fields in which there is a consensus among scientists. But the reality at the forefront of science is very far from this image, and in parallel to facts and established assessments, passions and emotions are buzzing in it, and there are conflicts, personal interests and social considerations, which are not much different from what we are familiar with from other areas of human activity.  
A good example of this is the fierce conflict taking place these days at the forefront of theoretical physics over the value and status of string theory (some hold "string theory". However, the singular form is more accurate). This conflict takes place not only on the pages of professional journals, but mostly in books, in the general press and even on the news platforms of the blogs, and it can be called "the battle over string theory".

In the last year, two books appeared dedicated to the attack on string theory: "Not Even Wrong: The Failure of String Theory and the Search for Unity in the Laws of Nature", by Peter Woit (Woit), a mathematician from Columbia University in New York, and "The Problem with Physics: The Rise of Theory The string, the fall of science, and what's next", by Lee Smolin, a physicist from the Perimeter Institute for Theoretical Physics in Canada. At the time of writing, the two books are ranked 78th and 15th, respectively, on Amazon's physics bestseller list. In contrast, the best-selling books of Brian Greene (Greene), also from Columbia University in New York, which describe string theory to the general public - "The Elegant Universe" and "The Fabric of the Universe" - are in the 8th and 21st places of the same list. In addition to his book, Peter White also writes a blog on the Internet with the same name and purpose as the book. In contrast, Lubos Motl, a physicist from Harvard University, maintains an opposing blog called "The Attribution System".

In order to understand the controversy and what is at stake, we will first have to ask: "What is string theory?" Today, theoretical physics relies on two solid pillars: on the one hand, quantum field theory is the language of the standard model of the elementary (subatomic) particles; And on the other hand Einstein's theory of gravitation known as "general relativity". In the decades that have passed since these teachings were proposed, they have been verified in a variety of experiments and a broad theoretical understanding has been acquired regarding them. However, new and deep questions also arose in their wake. We will mention some of the central ones.

Quantum gravity: Einstein's theory of gravity is not integrated into quantum theory (the surprising laws that govern the subatomic world). In fact, it can be shown that at distances shorter than the Planck distance, whose value is about a cm (that is, less than a millionth of a millionth of a millionth of a millionth of a single atom), the laws of physics must be different, or at least new laws must be added to them. At the same time, there is no necessity for quantum theory to raise a practical problem as long as a technology is not developed that would allow a glimpse at such tiny distances, and it is hard to believe that this will be available to us in the foreseeable future.

The unification of forces: Today, all physical forces are explained as derived from four basic forces (interactions): gravity, electricity, the weak nuclear force (which causes, among other things, the radioactive beta decay) and the strong nuclear force (which attracts the protons and neutrons in the nucleus despite the electrical repulsion between the protons). The question then arises: are there connections between the various forces, or do they have a common source? (Actually, such a partial relationship is already known for the electric force and the weak nuclear force).
Physical mechanisms for mass and charge: We know the basic properties of many particles, such as mass and charge. But what is the origin of these: are there physical mechanisms that determine them, or should they be accepted as axioms in mathematics and there is no point in trying to understand their origin?

String theory is a physical theory that addresses these questions. Its central physical idea is remarkably simple: suppose each particle is a small loop of vibrating string. The loop is so small that it looks like a dot. All the particles are made of the same type of string, and different modes of vibration are responsible for their different properties, just as the different sounds of the guitar are all produced from the same strings.

Despite the simplicity of the idea, complex quantum calculations were still required for the surprising discovery that string theory describes the force of gravity, and hence its main merit in being, apparently, a quantum theory of gravity. In addition to this, it offers answers to the question of the unification of forces, to the question of the physical mechanisms responsible for the properties of the particles and other key questions that arouse great interest among researchers.

These properties of string theory attracted a large number of leading scientists to the field, whose skills are indisputable: Edward Witten (Witten) from Princeton, who is considered the greatest theoretical physicist of our time; John Schwarz (Schwarz) of Caltech; Michael Green (Green) of Cambridge; Leonard Susskind (Susskind) of Stanford; Israeli researcher Natan Zeiberg from Princeton; Joseph Polchinski of Santa Barbara; Andrew Strominger of Harvard; and many others, including physicists in almost all universities in Israel. But even among the critics of the Torah there are senior scientists, among them the Nobel laureates Gerard T'Hooft and Sheldon Glashaw.

We will content ourselves with this brief description of the Torah and ask: if the Torah of the Hitar has so many achievements, what is the source of the controversy?

The central problem of the Torah is that, despite nearly 40 years of research, out of a very intensive research content in the last 22 years, no experimental evidence has been found for it so far. Although there is a chance that the Torah will be confirmed through direct detection of the string, if it is large enough, in one of the accelerators that will be built in the near future, or indirectly, through super-precise measurements. However, as long as there is no clear idea of ​​the size of the string, and it can be as small as Plank's size, it is very possible that even in the distant future it will not be possible to decide on its existence. Over the years, many young theoretical physicists chose to join the field, but at the same time the opponents multiplied, and the conflict that began as scientific and matter-of-fact became heated and moved to personal and "political" lines.

Opponents claim that the lack of experimental confirmation today, as well as in the foreseeable future, takes the Torah out of the realm of experimental science into the realm of mathematics and even into the realm of faith, due to the practical impossibility of a decisive examination of the Torah experimentally. They claim that the request of the researchers in the field for "additional time" should not be accepted, because despite the long time that has passed since string theory was first proposed, and despite the progress in its theoretical understanding, it has not come even close to the experimental field, while the explanations for it have changed time and time again. The critics add and claim that the leading researchers in the field are unable to admit their mistake, as their scientific conscience dictates, due to considerations of status and prestige and due to the fear of losing resources, including research budgets and students.

In contrast, the supporters of string theory point to the great theoretical progress that has been made in understanding the Torah in recent decades, to the important ideas and answers that have been added (some of which we have already mentioned) and to the influence that these ideas have had in the fields of mathematics, such as high-dimensional geometry, as well as in certain fields of physics, such as black holes as well as models of the particles and fundamental forces that can be tested in the particle accelerator that will soon be completed in Geneva. They emphasize the fact that many critics of string theory do not know it in depth, and some do not even know its basic principles. They also point out that many of the visitors are older physicists, who were late getting on the train, or physicists who tried to fit in and were frustrated by their lack of success, and these are also the ones who are jealous of the string people because of the attention and resources they began to gain after spending many years in the "scientific wilderness".

Some followers of the Torah have even increased their efforts and claim that the time has come for a revolution in the concept of science itself. According to them, since in the foreseeable future it will not be possible to conduct experiments at Planck distances, the experiment itself should not be seen as the central yardstick for physical theory, but the correct theory should be found with the power of logic alone.

Indeed, this is a struggle in which the personal and creative element plays an important role, in contrast to the "dry" and objective image of science. At a time like this it is good to remember that experience shows that the end of the scientific truth will come out, and this is much more convincing than loud confrontations.
 for further reading

"Not Even Wrong: The Failure of String Theory And the Search for Unity in Physical Law", Peter Woit, Publisher: Basic Books (2006).

 "The Trouble with Physics: The Rise of String Theory, The Fall of Science, and What Comes Next", Lee Smolin, Publisher: Houghton Mifflin (2006).

"The Elegant Universe - Superstrings, Hidden Dimensions and the Quest for the Ultimate Theory", Brian Greene, Publisher: Vintage (1999).

"The Fabric of the Cosmos: Space, Time, and the Texture of Reality", Briane Greene, Publisher: Alfred Knoph (2004).