Brane cosmology

The Branenkosmologie is a frequently (but not only ) discussed in the context of string theory theory, which assumes that in addition to the four usual in cosmology space-time dimensions, one or more additional dimensions ( extra dimensions ) exist. The four-dimensional spacetime is thus a hyperplane, called Bran ( of membrane), which is in a higher-dimensional space-time, the so-called bulk, embedded. Ordinary matter is trapped on the industry, which means that they can not escape into the extra dimension (s ). The extra dimensions are therefore not noticeable in everyday life. However, they have an influence on the expansion history of the universe, which provides a possibility for experimental verification of Branenkosmologie.

History

In 1914, was proposed a fifth dimension by Gunnar Nordström and 1919 by Theodor Kaluza in a letter to Albert Einstein and 1926 by Oskar Klein. In this way they wanted to achieve a unification of gravitation and electromagnetic force. The idea of ​​extra dimensions was later taken up by string theory. Is common to these theories that the extra dimensions compactified, rolled that is, are. The Kompaktifizierungsradius lies approximately at the Planck length. This means that the extra dimensions are so small that they neither can still be perceived in previous experiments in everyday life. An object that moves in the direction of one of these dimensions would almost instantly arrive back at its starting point.

Only towards the end of the 1990s, a model was developed, the Randall - Sundrum model, which allowed for an infinitely large, so do not kompaktifizierte, extra dimension. The aim of this model was to solve the hierarchy problem, namely to find an explanation for that gravity is weaker by orders of magnitude than the other forces of interaction. The Randall - Sundrum model represents the first Branenmodell dar. Over the past years, a variety of other models developed in their effects differ significantly (eg, the expansion of the universe ) in part of the original model. The Branenkosmologie is thus no single theoretical entity but consists of many different models.

So far, no experimental evidence of a further dimension were still found. However, the analysis of experiments at the Large Hadron Collider in December 2010 limits the possibilities of theories with infinite extra dimensions considerably.