Challenges Against The Front Grand Unified Theories

Zavarbashi, Amin | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48521 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Golshani, Mehdi
  7. Abstract:
  8. Many physicists believed that all four forces were once unified at high energy levels but as the universe reduced into a lower-energy states the inherent symmetry between the forces began to break down.this broken symmetry caused the creation of four distinct forces of nature. The goal of the unified theory is an attempt to look back in time to when these forces where unified as one. In this thesis I tried to give an overview of the challenges which is againsted theorists in the way of unification. In the first chapter explores the theory that try to unify the electromagnetic and weak forces are investigated.it is done by considering guage principle and spontaneous symmetry breaking.in the second chapter we discussed the first attempt to unify all forces (except gravity) which was done by Georgi and Glashow. Our goal is to find simple group which contains Standard model group and an irreducible representation for fermions such that they have right property under standard model group transformation.trying to incorporate gravity with all the other forces is a key insight thet many physicists hope a theory of quantum gravity will offer.in the last two chapter we emphesis on on two point of view toward Quantum theory of Gravity
  9. Keywords:
  10. Electroweak ; Grand Unified Theory (GUT) ; String Theory ; Quantum Gravity ; Loop Quantum Gravity

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