Cosmological perturbations in Horava-Lifshitz theory without detailed balance

Understand

In the Horava-Lifshitz theory of quantum gravity, two conditions -- detailed balance and projectability -- are usually assumed.

• The breaking of projectability simplifies the theory, but it leads to serious problems with the theory.
• The breaking of detailed balance leads to a more complicated form of the theory, but it appears to resolve some of the problems.
• Sotiriou, Visser and Weinfurtner formulated the most general theory of Horava-Lifshitz type without detailed balance.