摘要: String theory is a physical model that represents elementary particles by vibrating strings with the aim of unifying the four forces of nature (gravitational, electromagnetic, strong nuclear, and weak nuclear). As a closed string (ie a loop) moves through space, it may split into two (corresponding to fission), which may later recombine into one (corresponding to fusion). The path traced by a closed string in space-time is a (Riemann) surface, which has one hole (ie is of genus one) and two ends in the just mentioned example:1 particle 2 particles 1 particle TimeWhile string theory is one of the main paradigms in physics today, strictly speaking it is not a physical theory at all as it has yet to make any experimentally testable physical predictions. However, string theory has made (and continues to make) plenty of mathematical predictions. Thus, mathematics (especially geometry) has so far been the only “testing ground” for …