Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Escaping the crunch: gravitational effects in classical transitions   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. We show that the repulsive nature of domain walls, and the de
Sitter expansion associated with a positive energy minimum, can allow for
classical transitions to vacua of higher energy than that of the colliding
bubbles. Transitions can be made out of negative or zero energy (terminal)
vacua to a de Sitter phase, re-starting eternal inflation, and populating new
vacua. However, the classical transition cannot produce vacua with energy
higher than the original parent vacuum, which agrees with previous results on
the construction of pockets of false vacuum. We briefly comment on the possible
implications of these results for various measure proposals in eternal
inflation.

28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol