Null Energy Condition Violation and Classical Stability in the Bianchi I Metric

Understand

The stability of isotropic cosmological solutions in the Bianchi I model is considered.

• We prove that the stability of isotropic solutions in the Bianchi I metric for a positive Hubble parameter follows from their stability in the Friedmann-Robertson-Walker metric.
• This result is applied to models inspired by string field theory, which violate the null energy condition.
• Examples of stable isotropic solutions are presented.