In this paper, the knotlike cosmic strings in the early universe are discussed. We derive the cosmic string structures from the non-zero torsion tensor, and reveal that these strings are just created from the zero points of complex scalar quintessence field. In these strings we mainly study the knotlike configurations, and have constructed a new topological invariant for them. It is also shown ...

In this paper the collision of two cosmic string loops is studied. After collision junctions are formed and the loops are entangled. We show that after their formation the junctions start to unzip and the loops disentangle. This analysis provides a theoretical understanding of the unzipping effect observed in numerical simulations of a network of cosmic strings with more than one type of cosmic...

Cosmic strings are predicted by many field-theory models, and may have been formed at a symmetry-breaking transition early in the history of the universe, such as that associated with grand unification. They could have important cosmological effects. Scenarios suggested by fundamental string theory or M-theory, in particular the popular idea of brane inflation, also strongly suggest the appeara...

It is possible that superstrings, as well as other one-dimensional branes, could have been produced in the early universe and then expanded to cosmic size today. I discuss the conditions under which this will occur, and the signatures of these strings. Such cosmic superstrings could be the brightest objects visible in gravitational wave astronomy, and might be distinguishable from gauge theory ...

The Hubble Space Telescope Treasury Program images collected as part of the Cosmic Evolution Survey were used to develop a new technique for identifying gravitational lensing events resulting from a less-massive cosmic string. By employing Monte Carlo simulations of cosmic strings embedded within the survey, galaxies were decomposed using Hermite Polynomial shapelets, and compared with the unal...

P-term potentials can give rise to Nielsen-Olesen or semi-local cosmic strings. We present a general analysis of these cosmic strings where we derive the Bogomol’nyi equations and field profiles for both types of string and discuss their stability. We give an analysis of the fermionic zero modes that could live on the strings and a brief discussion of the inflationary period preceding their for...

It has been speculated that cosmic string networks could produce ultra-high energy cosmic rays as a by-product of their evolution. By making use of recent work on the evolution of such networks, it will be shown that the flux of cosmic rays from cosmologically useful, that is GUT scale strings, is too small to be used as a test for strings with any foreseeable technology.

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We address the question of finding stable and metastable cosmic strings in quasirealistic heterotic M-theory compactifications with stabilized moduli. According to Polchinski’s conjecture, the only stable strings in the absence of massless fields are Aharonov-Bohm strings. Such strings could potentially be created in heterotic compactifications as bound states of open membranes, five-branes wra...