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Difference between String theory and Loop quantum gravity theory in physics?

Category : All, Education · by Mar 31st, 2015

Difference between String theory and Loop quantum gravity theory in physics?

Science works by trying to explain the world around us. Various theories predict the occurrences in the Universe around us generating more fields of studies. Physics is one such field which tries to explain why things act the way they act. Laws like Newton’s laws, the three laws of thermodynamics etc. are the basis of physics. Famous scientists use these observations to see patterns and propose a theory on the same after which these theories are thoroughly ascertained and verified to be true.

There are two major problems in Physics right now.

One is the explanation of the microscopic world consisting of atoms and molecules and how they interact with each other. For understanding these phenomenons, knowledge of quantum mechanics can help us understand them quite sufficiently. The second problem is the study of much larger objects, like galaxies and solar systems, blackholes etc. where the knowledge of general relativity can be used. Quantum mechanics works well with small objects but fails to explain large phenomena whereas general relativity explains large phenomenon with ease but doesn’t really work for small objects. With recent studies, it is seen that quantum mechanics mostly works with its own assumptions on a large and small scale with their own assumptions but cannot work combined. Many scientists have tried to propose a theory of everything to explain the relation between the two scales but have not succeeded yet.

Study of this theory of everything

Study of this theory of everything has brought about an overflow of theories but only two theories really stood up. These were “String Theory” and “Loop quantum gravity”. String theory states that the smallest particles in the universe are actually made up of strings or waves. These ‘strings’ are the constituents of everything in the world. The vibration of these strings causes properties like magnetism, spin etc. This concept is now the M theory in which a total of 11 dimensions are considered and research goes on to how the strings can be modelled in different configurations.

Prior to string theory, there existed loop theory or loop quantum gravity that said that all objects could be drawn in terms of spin networks which defined how the object exists in space-time. These spin networks are not physical objects but drawings of objects in space time. Loop theory also tries to solve a lot of problems similar to string theory but does not make use of higher dimensions to solve them. Both have to follow the mathematical rules and cannot stray from them.

Which of the theories is better is not yet known as both the theories are not yet practically proved. However, the M Theory is relatively recent (1995) compared to loop theory (1986). Both the theories are not really testable so both stand true until either one is disproved or approved.

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 Viswas Purohit, MS,PhD | Guest Author |

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7 years ago · Reply

This is the type of information I was looking for my brother. I’ll be sure to direct him here.

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