QUANTUM FIELD THEORY AND STRING THEORY

Abstract It is known that scientific innovations discovered in modern times prove that the structural dynamics of the Universe are subject to very complex laws. Combining all these laws into one theory is an issue that scientists have always believed in and worked on. It is this theory that can fully explain the dynamics and structure of the Universe, as well as many phenomena in terms of quality and quantity. This theory also has the potential to answer important questions about the beginning of the Universe. Today, quantum field theory is considered the closest theory to this theory. Quantum field theory is an important framework that plays a fundamental role in modern theoretical physics, unifying quantum mechanics and special relativity. The emergence of this theory arose from the need to overcome the separation of classical field theories and quantum mechanics - which occurred separately. At the beginning of the 20th century, it became possible to explain the effects of combining quantum mechanics with the concept of fields to clarify the properties of subatomic particles, as well as the properties of particles. It is currently considered one of the most accurate theories in physics. However, on the other hand, there is also String theory, which could be worthy of being a theory of everything. String theory suggests that the smallest structural unit of the universe consists of strings vibrating at different frequencies. Since the universe was actually created from a single point by the Big Bang, we conclude that matter and the physical field have the same source. This source is the smallest structural unit of the universe, namely strings. From this it becomes clear that quantum field theory can actually be described by string theory, and this description can unite these two theories around one goal. In this article, all the features of quantum field theory are examined, and an attempt is made to explain these features and the contradictions it encounters with string theory. The issues that string theory and quantum field theory can explain are reviewed. The shortcomings of quantum field theory are examined and the reasons for this are touched upon. Finally, ways to combine quantum field theory and string theory and include it in the final theory of the universe are mentioned.