title: Topological defects in contracting universes.
abstract: We study the behavior and consequences of cosmic string networks in contracting universes. They approximately behave during the collapse phase as radiation fluids. Scaling solutions describing this are derived and tested against high-resolution numerical simulations. A string network in a contracting universe, together with the gravitational radiation it generates, can affect the dynamics of the universe both locally and globally and be an important source of radiation, entropy, and inhomogeneity. We discuss possible implications for bouncing and cyclic models.
authors.affiliation: Centro de Fisica do Porto e Departamento de Fisica da Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal. ppavelin@fc.up.pt
authors.forename: P P
authors.initials: PP
authors.lastname: Avelino
authors.forename: C J A P
authors.initials: CJ
authors.lastname: Martins
authors.forename: C
authors.initials: C
authors.lastname: Santos
authors.forename: E P S
authors.initials: EP
authors.lastname: Shellard