String Theory Mihir John What are the most basic constituents that make up the universe around us?

Why use String Theory? String Theory is believed to bridge the gap between General Relativity and Quantum Mechanics This is because Relativistic Quantum Field Theory only works when gravity is ignored (very weak) General Relativity only works when we can assume the universe can be described by classical physics (no quantum mechanics)

String Theory Suppositions In string theory, particles come from excitations of the string The theorized particle with gravitational force, with zero mass and two units of spin, is called the Graviton Even though the graviton is compatible with quantum theory, the mathematics of the interactions does not follow String Theory allows that these particles collide over a small, finite distance

String Theory Basics With string theory attempting the explain Quantum Gravity, the strings exist near Planck length (10^-33cm) Multiple types of string theory exist, and are classified by open/closed strings and also supersymmetry. (bosons and fermions) Different string theories require different spacetime dimensions to work—Range from 10 to 26

String Theory Unification If “strings” are the most basic constituents of the universe, and all particles arise from their excititation, then all matter and the forces of nature arise from strings If everything arises from one system, is a unified theory not possible?

Supporting String Theory Experimental data from particle accelerators such as CERN could provide insight Primarily, comparing energy levels from collisions could support the theory of additional dimensions Particle accelerators could also provide data for theorized particles such as the graviton

Additional Sources TEDTalk- Brian Greene-Making Sense of String Theory