Density of strings formed at a second-order cosmological phase transition
Abstract
We discuss the problem of estimating the characteristic length scale
ξ
s
, and hence the initial density, of a system of cosmic strings formed at a continuous, second-order phase transition in the early universe. In particular, we examine the roles of the correlation length (or string width)
ξ
c
and the Ginzburg length
ξ
G
which defines the ``fuzziness'' of long strings. We argue that strings acquire a clear identity only once
ξ
s
exceeds both
ξ
c
and
ξ
G
, and estimate its magnitude at that time.