Extra Dimensions
Extra dimensions may form the basis of some fundamental theories in physics. One may wonder why we would believe in extra dimensions, how they are described in physics and how we search for them. Space-time coordinates form the basis of Einstein's theory of General Relativity, which describe the
geometry of the universe, the behaviour of gravity and therefore the physics at large scales. However, for physics at the very small scales we resolve to the Standard Model (SM). The SM describes electromagnetism, the weak and the strong nuclear forces and it is build upon the framework of quantum mechanics. The quest now is to find one unifying theory that includes both GR and
quantum mechanics in one formally coherent mathematical structure. Unfortunately so far it has been extremely difficult, if not impossible, to reconcile GR with quantum mechanics and in particular to unify gravity with the other forces of nature. The quest for uni cation may be considered as the
holy grail of modern physics and it turns out that extra dimensions provide a very useful tool in addressing the problems. In fact, the most promising unifying theories, including String theory, are only consistently written in a universe that consists of 10 or 11 space-time dimensions. This implies the existence of an extra 6 or 7 spatial dimensions.
Depending on the type of metric in the bulk, ED models fall into one of the following two categories:
- Flat, also known as universal ED models (UED): The metric on the extra dimensions is chosen to be flat. For simplicity N = 1 or N = 2 UEDs are
considered. The notion of KK parity is fundamental to UED models, which springs from the geometrical symmetries of the compacti cation. In general, UED models respect KK parity and has important consequences for their collider and astrophysical phenomenology. The UED models are very peculiar: the extra dimension is an interval with a background geometry and KK parity is realized as a geometric reflection about the midpoint of the extra dimension. In fact, KK parity has a larger parent symmetry, the KK number conservation, which is broken only by the interactions living on the orbifold boundary points.
- Warped ED models.
Theoretical Physics
9 年Mr Ashfaque,if you want, you can come on the FQXi Platform.Mr Tegmark has created this Platform with Mr Aguirre and the MIT.Scientists can discuss about their models.For example,Mr Tegmark has put an article about consciousness.It exists also an essays'contest.The topic this year is the observer.Regards
Theoretical Physics
9 年by geometrical algebras, Clifford, lie....In fact if we want explain gravitation at 10^-35m and more far, we are always in a pure 3D .The volumes and mass and fields are essential in 3D for the respect of our proportions.Extradimensions are not really relevant .It is just a play of maths wanting to explain the different scales above our standard model and our heat ,thermo and electromagnetism.The gravitation for example can be explained with a pure cause, a particle produced by BH for example and this particle is encoded like our bosons in our nucleis in a pure 3D correlation for our proportions and constants.
Theoretical Physics
9 年Hello, I am not convinced about these extradimensions.A dimension for consciousness, a dimension for this or that.We live in a pure 3D evolutive space time relative with our spacetime.The determinism must be an essential.I beleive that these extradimenison are just implied by geometric
Telecom Engineer(consultant ) at WorleyParsons till Dec2017.
9 年Well Considering the Theory of Relativity and Quantum Physics Dimensions can be defined and work upon in a complex form as its is happening in the Scientific World. We need to look at the Formation of Universe and the Sustenance of same for Billions or Millions Year which no Human or Scientist has definitively Figure out. The important thing which needs to be looked at is The so called Scientific Inventions are mere Discoveries of Nature assimilated to get result to perform certain Task. What is required is an different approach towards gathering evidence and relative information on Mystery of Magnetism per se and Gravitational Force created around the Cosmic bodies which holds them in a position till their existence. Once the mystery of this discovery is resolved the Quantum Physics and Theory of Relativity can be put to test to get far better information and improvement on discoveries of nature and variedly be used in Scientific approach to fulfill certain tasks enabling Human with choice of improvement and Destruction!!