Category:Unified Theories

From Eurêka

Unified Theories

Unified field theory Principle that all forces in the universe are part of a single concept.

Unified theory Generally, a theory that gathers a wide range of fundamentally different phenomena under a single precept, as in James Clerk Maxwell’s discovery that light and magnetism are aspects of a single, electromagnetic force. In particle physics, any theory exposing the relationships between seemingly disparate classes of particles.

Grand unified theories (GUT) Class of theories that purport to reveal identities linking the strong and electroweak forces. The differences between these forces in nature today is attributed to the breaking of symmetrical relationships among force-carrying particles as the very early universe expanded and cooled.

1. Grand unification theory (Grand Unification) Theory that unifies electromagnetic, strong and weak nuclear forces, a quantum field theory.
2. Grand unification energy Energy above which electromagnetic, strong, and weak nuclear forces become indistinguishable.

Gravitational theory Unification of gravity and quantum mechanics, a crucial step in the search for the theory of everything. It is the quest to explain what happened at the first moment of time or what happens at the center of a black hole.

Quantum gravity Laws of physics that are obtained by merging general relativity with quantum mechanics, a single framework that explains all the universe’s particles and forces.

• See also Quantum Physics

Theory of Everything

Theory of Everything (TOE) Theory that will be simple enough to write down as a single equation and its solution will describe a universe that is unmistakably ours, with three spatial dimensions and one time dimension; with quarks, electrons and other particles that make up everything; with gravity, nuclear forces and electromagnetism to hold it all together; with even a Big Bang from which everything began. The major paradigms of physics, including quantum mechanics and Einstein's gravity, will be revealed as intimately related.

Note : Claims of finding the TOE met with so much ridicule in the 1980s that string theorists became allergic to that sobriquet.

1. Relativity theory Space is curved and continuous. Einstein’s theory describes how the gravity of everything from subatomic particles to massive stars distorts and curves the 4 dimensions of space-time.
2. Quantum mechanics theory Space is not curved and granular. According to this theory which describes the motions of subatomic particles in so-called flat space, the forces of nature, except gravity, are transmitted by tiny bundles of energy called quanta.
   1. Granular Made up of units of vanishingly small lengths.
3. Loop quantum gravity Space is curved and granular, but not continuous. Theory that represents the structure of space by describing its effects on imaginary rotating particles.
   1. Rotating particles Each particle spins on an axis and moves through space in an elliptical trajectory. As the particle returns to its original position, it is oriented slightly differently because of the curvature of space, or gravity.
   2. Spin network Web formed by different trajectories of various particles which contains information about the structure of space.
   3. Spin foam Spin networks spread over time. Each spin network is a snapshot of space at a particular instant, when stretched together over time they describe the structure of space and time.
   4. Spin net Abstract mathematical object from which space is constructed that provides a snapshot of the geometry of three-dimensional space at a particular instant.

Quantum space-time Spin nets and spin foam cannot be thought of as existing in space and time. They reside on a more fundamental level, as a deep structure that underlies and gives rise to space-time. Thus they have been called quantum space-time.