1. Inspiration of the Super String theory
Most of us are aware of Albert Einstein’s biography to some extent. In the last part of his life, he devoted himself to the greatest task to figure out the “Theory of Everything.” The theory or model that can describe all the interactions, phenomena and realms of reality. When he passed away on April 14, 1955, at Princeton, he left the unfinished manuscripts of his legendary works on his table. Perhaps, he was unable to do that due to two shortcomings: The limit of technologies and the knowledge about the fundamental forces of the Universe. It concludes that the idea of the Theory of Everything dates originally to the time of Einstein himself.
As Einstein probed a completely new way that we look at the universe improving Newton’s work through his two legendary papers; Special and General Theory of Relativity, it successfully described the Laws that govern Universe at large scales. However, in the 1900s eminent Physicists like Max Planck, Erwin Schrodinger, and Heisenberg realized that the law that governs the Universe at small scales behaved so unique from larger scales and that math can’t describe it. Rather it required another branch of complete theory to describe it. It gave birth to “Quantum Mechanics.” So far, there are two theories, “Einstein’s Relativity,” and “Quantum Mechanics,” which describes the Universe we perceive.
2. Development of Super String Theory
Well, Super String Theory is one of the candidates which is inspired by Einstein’s dream of achieving the Grand Unified Theory. The successful theory should fulfil the following criteria: The theory should unify all the known laws of physics governed by four fundamental forces of the Universe. It should explain the origin and end of the universe: The Big Bang and the Blackholes which current theories can’t understand much. Should predict and visualize the ultimate building blocks of the Universe. Solve the mysteries like dark matter and energy Should yield testable observations The closest achievement that we got so far is the standard model which comprises elementary particles and three force interacting particles. It is ‘one of the finest,’ achievements in physics. However, we still know it is incomplete.
1. No clue about gravity in the model: The model doesn’t include gravity as one of the fundamental forces. There is a breach between the classical and quantum understanding while other forces can be described by interactions on the quantum level.
2. Dark Matter mystery: It does not give any clue to the dark kinds of stuff that make up 95% of the entire Universe.
3. Baryon Asymmetry: If Universe began from the Big Bang, the Energy lead to pair production that could have produced the same amount of matter and anti-matter. However, the current universe is matter dominated. There is no anti-matter remaining somewhere.
4. Origin of Neutrino masses: The neutrinos are not massless but their origin of masses can’t be explained. And all neutrinos are left-handed and right-handed, left-handed anti-neutrinos are not observed. Maybe the solution could explain the Baryon Asymmetry.
The gravity when plugged into the standard model should have its particle called the graviton. But the quantum correction on the graviton is inconsistent with the quantum theory and it is a very tough job. It results in unavoidable infinities and probabilities greater than one that makes no sense to the description of reality. So, combining gravity with the standard model requires another concept called quantum gravity that requires quantized space to explain it.
(Fig 1 :The particles can be represented as one dimensional strings according to the theory).
Image: soyastudio.com
3. Features of String theory
The string theory is the collective effort of many theorists who have dedicated their lives to research and are still on the verge of its development. The string theory is based upon the simple idea that the point particles of the standard model are just an approximation. If carefully observed through the particles with resolutions high enough, they can be viewed as one-dimensional strings that can be considered as the Planck length. The strings can be open or closed. It can vibrate into different modes of oscillation(s): One, two three etc… It’s due to these different oscillations that one string can resemble different particles. It is that when strings are excited gives the intuition of different particles. It means that the point-like particles that we see are just the result of the excitement of strings that results in the intuitions. The math describes the interactions and existence of the gravitons at the quantum level. If the particle is a point, it traces its trajectories which can be resembled by lines. When they are represented by strings, it can trace a surface and thus can explain all the probabilities of the interactions thus ignoring the infinities when describing graviton properties.
However, there are still anomalies in this theory: First, the theory is based upon the concept of Supersymmetry meaning that as much as there are fermions there should be Bosons. But till now no symmetry is found. According to this, there are still spaces in the Standard model that should be filled by the new particles. The string realizations of point particles work only in 26 dimensions which is far from describing the four dimensions of the Universe in which we live. Even simplifying the theory works only in 11 dimensions which sounds like it is just mathematical nonsense. There is no direct evidence that point particles are composed of strings due to technological limitations. There we are not sure whether the strings are correct or not. However, theorists are not annoyed by the shortcomings. They are treated as positive clues for revealing even deeper truths that the universe has to offer. The hunt for super symmetries is made to hunt for particles like ‘Axions,’ which is a ‘probable candidate’ for the dark matter particles. The extra dimensions that emerged from the theory made them make two hypotheses: It can explain the weakness of gravity as compared to the other three forces. It explains as gravity has only access to the hidden dimensions that are curled up. Upon acting it is distributed in all dimensions so that the intensity of gravity we feel is just a share of its magnitude assigned to four dimensions that we perceive. As the dimensions can curl up and resembles any geometry allowed by the math, it gives the idea of a ‘Multi-universe,’ that has different configurations of dimensions. As the strings can be closed or open, it can also solve Blackhole information Paradoxes.
4. Conclusion
So far the theory has been so promising. The future goal for the theory of everything is such an exciting scope. The Noble prizes are waiting for any breakthrough that we anticipate. Therefore, it is always fun to keep in touch with what they have to offer and read textbooks titled, “THE GRAND UNIFIED THEORY!” Perhaps I wish it may happen in our time.
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