D-Brane

In string theory D- branes are (English D- branes [ di ː bɹeɪns ] Origin of the name see definition ) to schedule a special class of p- branes, to which the ends of open strings. The concept comes from Joseph Polchinski (1989).

Definition

D- branes (or Dp - branes ) are defined as a p- dimensional objects that couple to the open strings which satisfy Dirichlet boundary conditions. The number of dimensions p thereby indicates the number of spatial dimensions, each D- brane has additionally an extension in the time direction.

Variations of the term are:

  • D- membrane ( = D2 - brane )
  • D- String ( = D1 - brane, not to be confused with the F- string, ie the fundamental string )
  • D- particles ( = D0- brane )
  • D- instanton ( = D (-1) - brane ).

You can D- branes as special cases of certain classical configurations ( " solitons " ) interpret. You can be infinitely extended, but also a finite and even vanishing volume.

Origin

D- branes is thought of as low-dimensional, dynamic objects before, embedded in a bulk, ie in a higher-dimensional space-time or in a hyperspace. They are part of string theory (see also M- branes in M- theory). Since this describes a 10 1- dimensional space, the question arises why we can perceive (with time ) only 3 1 dimensions. As an explanation to offer this very branes.

According to string theory, there are one-dimensional strings whose ends are open and closed circular strings. Strive to " attach " to a Brane to strings with open ends; they can no longer arbitrarily change the dimensions, but are "trapped " in their Brane. Interactions with particles in the bulk will then take place only very limited. If we know the universe is composed of such particles that are trapped in a Brane, the people can not leave this universe and are limited to the low dimensional space. These properties lead to the idea that our universe could consist of one or more D3 - branes (corresponding to "our" perceptible three spatial dimensions). The strings attached are accordingly almost all elementary particles, such as photons, electrons, quarks.

Annular strings, however, are not bound to a brane, but exist in the bulk. They interact only limited with the particles in the brane, instead spread its power on several dimensions. Today, about the graviton, the gauge boson of gravity is considered as a candidate for such a particle. This would explain why the Great unified theory so far includes only three of the four fundamental physical forces and why the gravity in relation to the other fundamental forces is so weak. At the same time thus lends itself to an elegant solution to the dark energy and dark matter. Because of the possibility of the graviton to move between the branes and thus interact with different branes, a different universe with the gravitationally could occur in our interaction, what we would perceive as dark energy or dark matter. On the other hand, it would also mean different from the current law of gravity.

Due to quantum effects and gravitational interactions D- branes can be deformed and excited to vibrate. A satisfactory mathematical treatment of this phenomenon does not exist. There is evidence that D- branes can be unstable and decay. Similarly, some highly deformed (eg spherical ) D- branes are known that can occur in curved spaces. The classification of all possible D- branes is an open problem of great importance for the understanding of string theory, in particular its vacuum structure.

Other considerations lead to more of these branes exist and represent parallel universes. Since branes can move freely in the room itself, could collide two branes. It would be so much energy is released as it is only conceivable in the Big Bang. From this derives the ekpyrotische universe, so the idea that our universe was created by such a collision.

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