String theory : Moving closer to a theory of everything
Introduction
As our knowledge increases we tend to see that what is unknown is also increasing and as we study the four fundamental forces of nature, that is electromagnetic force, gravitational force, strong nuclear force and weak nuclear force, we cannot say that these are the only forces of nature but our known fundamental forces of nature. Let’s get to 1600 where William Gilbert stated that earth is also a giant magnet and that is the reason the magnets point towards the north-south direction(geomagnetic north and south poles). In the 1800s Hans Christian oersted and Michael Faraday found out the relationship between electricity and magnetism, we get that these two forces are the same known as electromagnetic force. And there was the Newton’s law of gravitation but after Einstein found out in the year 1905 (known as his year of miracles) he discovered the Special theory of relativity and then General theory of relativity this unified gravity, space, time and the speed of light, the famous equation, E=MC^2,which led to further understanding on nuclear forces (the research on atom bomb, Manhattan project). Slowly we tried to create a theory of everything from what we know, the supersymmetry postulates, the discovery of Higgs in 2012 in large hadron collider at cern. Now as we go deeper into the nucleus – protons and nuetrons, inside protons and nuetrons there are quarks, the quarks is still not the end, the charecteristic property of being a quarks for nuetron and quarks of protons are vibrating strings which vibrates in a charecteristic way to give the specific property of nuetrons, neutrinos, electrons etc,now this our string theory which is the best one to be used as the “Theory of everything” .
String theory – an overview.
The string theory simply states that the charecteristics of the protons, nuetrons and neutrinos is due to difference in vibration of strings in them or inside the quarks, this is just like musical notes producing charecteristic music according to the vibration of strings in a guitar or violin. Our normal number of dimensions is 3 and along with the dimension of time but string theory needs more dimensions and after further analysis string theory requires 10 dimensions and the dimension of Time, there are dimensions which are of micro level (among the ten) and not seen by us. Just like pole looks 2d from afar….
We can see only 3 dimensions, the other dimensions are time and other miniature curled up dimensions affects the so called vibration of strings which indeed affects the charecteristic of the resultant particle and hence these 3 +7 +1 dimensions are required in string theory.
History of string theory
String theory was first studied in the late 1960s as a theory for the strong nuclear force, Subsequently, it was realized that the very properties that made string theory unsuitable as a theory of nuclear physics made it a promising candidate for a quantum theory of gravity. The early version of string theory, the bosonic string theory included only the class of particles known as bosons . It was later developed into the superstring theory, which gives the idea called “supersymmetry” between bosons and the class of particles known as fermions. Five versions of superstring theory were developed before it was combined in the mid 1990s that they were all different limiting cases of a single theory in 11 dimensions known as M theory. In late 1997, theorists discovered an important relationship called the Anti de sitter or conformal field theory correspondence, which relates string theory to another type of physical theory called a quantum field theory
The M theory
M theory combines all the consistent versions of the Super string theory. M-theory may provide a framework for developing a unified theory of all of the fundamental forces of nature. Eventough a complete formulation of M-theory is not known, such a formulation should describe two- and five-dimensional objects called branes and should be approximated by eleven-dimensional supergravity at low energies . Modern attempts to formulate M-theory are typically based on matrix theory or the Ads/CFT correspondence
Relationship between the string theories
As physicists examined the string theories, they found out that they are more related in a more detailed and non trivial way.
Why it is called a “Theory of everything
A theory of everything , final theory, ultimate theory, or master theory is a single, all encompassing, theoretical framework of physics that fully explains and links together all physical aspects of the universe. String theory and M-theory have been proposed as theories of everything. Over the past few centuries, two theoretical frameworks have been developed that, together, most closely resemble a Theory of everything . These two theories upon which all modern physics rests are the general relativity and quantum mechanics. General relativity is a theoretical framework that only focuses on gravity for understanding the universe in regions of both large scale and high mass: stars, galaxies, clusters of galaxies etc. On the other hand, quantum mechanics is a theoretical framework that only focuses on three non gravitational forces for understanding the universe in regions of both small scale and low mass: sub atomic particles, atoms, molecules etc. Quantum mechanics successfully implemented the Standard Model that describes the three non gravitational forces, strong nuclear, weak nuclear, and electromagnetic force as well as all observed elementary particles
Conclusion
The Superstring theory or M theory had been partially successful in describing all that is known to us. Why I say partial means that a theory of everything should explain all the aspects in the cosmos, but this still is under development, and again whatever i know on string theory is mentioned herein. I might have missed some of important things. The Super string theory, the Supersymmetry postulates and then about dark matter, dark energy are all under development and hopefully in the coming decades some of them might be wrong but right now we are still moving closer to a theory of everything.
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