Fractal space, cosmic strings and spontaneous symmetry breaking

The present paper is conceived within the framework of El Naschie's fractal -Cantorian program and proposes to develop a model of the fractal propertie s of spacetime. We show that, starting from the most fundamental level of e lementary particles and rising up to the largest scale structure of the Uni verse, the fractal signature of spacetime is imprinted onto matter and fiel ds via the common concept for all scales emanating from the physical spacet ime vacuum fluctuations. The fractal structure of matter, field and spaceti me (i.e. the nature and the Universe) possesses a universal character and c an encompass also the well-known geometric structures of spacetime as Riema nnian curvature and torsion and includes also, deviations from Newtonian or Einsteinian gravity (e.g. the Rossler conjecture). The leitmotiv of the pa per is generated by cosmic strings as a fractal evidence of cosmic structur es which are directly related to physical properties of a vacuum slate of m atter (VSM). We present also some physical aspects of a spontaneous breakin g of symmetry and the Higgs mechanism in their relation with cosmic string phenomenology. Superconducting cosmic strings and the presence of cosmic in homogeneities can induce to cosmic Josephson junctions (weak links) along a cosmic string or in connection with a cosmic string (self) interactions an d thus some intermittency routes to a cosmic chaos can be explored. The key aspect of fractals in physics and of fractal geometry is to understand why nature gives rise to Fractal structures. Our present answer is: because a fractal structure is a manifestation of the universality of self-organisati on processes, as a result of a sequence of spontaneous symmetry breaking (S SB). Our conclusion is that it is very difficult to prescribe a certain typ e of fractal within an empty spacetime. Possibly, a random fractal (like a Brownian motion) characterises the structure of free space. The presence of matter will decide the concrete form of fractalisation. But, what does it mean the presence of matter? Can there exist a spacetime without matter or matter without spacetime? Possibly not, but consider on the other hand a sp ace far removed from usual matter, or a space containing isolated small par ticles in which a very low density matter can exist. Very low density matte r might be influenced by a fractal structure of space, for example in the s ense that it is subject also to fluctuations structured by random fractals. Diffraction and diffusion experiments in an empty space and very low densi ty matter could provide evidence of a fractal structure of space. However, at very high (Planck) densities, and a spacetime in which fluctuations repr esent also the source of matter and fields (which is very resonable within the context of a quantum gravity), we can assert that Einstein's dream of g eometrising physics and El Naschie's hope to prove the fractalisation (or C antorisation) of spacetime are fully realised. (C) 2000 Elsevier Science Lt d. All rights reserved.