Abstract
Cosmological data suggest that we live in an interesting period in the history of the universe when . The occurrence of any epoch with such a “triple coincidence” is puzzling, while the question of why we happen to live during this special epoch is the “Why now?” problem. We introduce a framework which makes the triple coincidence inevitable; furthermore, the “Why now?” problem is transformed and greatly ameliorated. The framework assumes that the only relevant mass scales are the electroweak scale , and the Planck scale and requires parametrically. Assuming that the true vacuum energy vanishes, we present a simple model, where a false vacuum energy yields a cosmological constant of this form.
- Received 5 June 2000
DOI:https://doi.org/10.1103/PhysRevLett.85.4434
©2000 American Physical Society