Escaping the crunch: gravitational effects in classical transitions

Understand

During eternal inflation, a landscape of vacua can be populated by the nucleation of bubbles.

• These bubbles inevitably collide, and collisions sometimes displace the field into a new minimum in a process known as a classical transition.
• In this paper, we examine some new features of classical transitions that arise when gravitational effects are included.
• Using the junction condition formalism, we study the conditions for energy conservation in detail, and solve explicitly for the types of allowed classical transition geometries.