Radiation from cosmic chiral string loops

The gravitational and electromagnetic radiation from chiral superconducting cosmic string loops is calculated. The formulas for energy, momentum, and angular momentum losses due to gravitational and electromagnetic radiation from chiral loops of an arbitrary configuration are derived. After summation over all modes, expressions for the corresponding radiation rates averaged over the loop oscillation period have the form of four-dimensional integrals. These formulas are reduced to sums over the kinks for loops composed of piece-wise linear strings. For three examples of string loops, the total radiation rates are calculated numerically depending on the chiral current along the string. In the limit of a nearly maximum current, which corresponds to a stationary loop (vorton) configuration, we determine the upper bounds on the gravitational and electromagnetic radiation. We also estimate the oscillation damping time of a nearly stationary loop.     

Baryon number generation from cosmic string loops

Baryon number generation due to the decay of particle-antiparticle pairs created from cosmic string loops is studied. In the situation when cusp evaporation occurs a significant baryon asymmetry (baryon/entropy ∼ 10⁻⁴ ϵ: ϵ is a net baryon asymmetry generated from one pair of particle-antiparticle) can be generated.     

Wilson loops T-dual to short strings

We show that closed string solutions in the bulk of AdS space are related by T-duality to solutions representing an open string ending at the boundary of AdS. By combining the limit in which a closed string becomes small with a large boost, we find that the near-flat space short string in the bulk maps to a periodic open string world surface ending on a wavy line at the boundary. This open string solution was previously found by Mikhailov and corresponds to a time-like near-BPS Wilson loop differing by small fluctuations from a straight line. A simple relation is found between the shape of the Wilson loop and the shape of the closed string at the moment when it crosses the horizon of the Poincaré patch. As a result, the energy and spin of the closed string are encoded in properties of the Wilson loop. This suggests that closed string amplitudes with one of the closed strings falling into the Poincaré horizon should be dual to gauge theory correlators involving local operators and a Wilson loop of the T-dual (“momentum”) theory.     

Self-gravitating strings and string/black hole correspondence

In a recent essay, we discussed the possibility of using polymer sizing to model the collapse of a single, long excited string to a black hole. In this letter, we apply this idea to bring further support to string/black hole correspondence. In particular, we reproduce Horowitz and Polchinki's results for self-gravitating fundamental strings and speculate on the nature of the quantum degrees of freedom of black holes in string theory.     

The stability of cosmic string loops

A general perturbation analysis is performed on closed string loops to investigate whether small perturbations cause the known class of non-self-intersecting loops to self-intersect. This leads to the conclusion that most of this class of loops are stable to small perturbations.     

Scaling solution for small cosmic string loops

The equation governing the time evolution of the number density of loops in a cosmic string network is a detailed balance determined by energy conservation. We solve this equation with the inclusion of the gravitational radiation effect, which causes the loops to shrink (and eventually decay) as time elapses. The solution approaches a scaling regime in which the total energy density in loops remains finite, converging both in the infrared and in the ultraviolet.