Title: "Entanglement as the source of black-hole entropy"
Cosmic strings are line-like defects produced during phase transitions in the early Universe. Since their energy density reaches a scaling regime rapidly after formation, they never dominate the Universe's energy density at late times and remain compatible with observations if their string tension is small enough. However, the existence of the scaling regime depends on the continous formation of loops from long cosmic strings at (auto-)intersection events. Once formed, the loops shrink (and eventually disappear) by graviational wave (GW) emission. Moreover, gravitational backreaction imposes that no loops should be formed below a certain cutoff scale.
I will present a phenomenological description of the cosmic string
loop number density distribution including the three effects of loop
formation, GW decay and backreaction. We use the Polchinski-Rocha (PR)
approach to describe the short-scale structure of long cosmic strings
and adjust their loop production function to fit numerical
simulations. We then extend the PR model below the backreaction cutoff
and discuss how the resulting distribution evolves through the eras of
radiation and matter domination. It is found that all loops reach the
so-called "full-scaling regime" after a short time. We then use
resulting universal number density distribution to study the
cosmological consequences of cosmic string loops.