Evading the pulsar constraints on the cosmic string tension in
  supergravity inflation
  The cosmic string is a useful probe of the early Universe and may give us a
clue to physics at high energy scales where any artificial particle
accelerators cannot reach. Although one of the most promising tools is the
cosmic microwave background, the constraint from gravitational waves is
becoming so stringent that one may not hope to detect its signatures in the
cosmic microwave background. In this paper, we construct a scenario that
contains cosmic strings observable in the cosmic microwave background while
evading the constraint imposed by the recent pulsar timing data. We argue that
cosmic strings with relatively large tension are allowed by delaying the onset
of the scaling regime. We also show that this scenario is naturally realized in
the context of chaotic inflation in supergravity, where the phase transition is
governed by the Hubble induced mass.
