Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How does gravity save or kill Q-balls?   We explore stability of gravitating Q-balls with potential
$V_4(\phi)={m^2\over2}\phi^2-\lambda\phi^4+\frac{\phi^6}{M^2}$ via catastrophe
theory, as an extension of our previous work on Q-balls with potential
$V_3(\phi)={m^2\over2}\phi^2-\mu\phi^3+\lambda\phi^4$. In flat spacetime
Q-balls with $V_4$ in the thick-wall limit are unstable and there is a minimum
charge $Q_{{\rm min}}$, where Q-balls with $Q<Q_{{\rm min}}$ are nonexistent.
If we take self-gravity into account, on the other hand, there exist stable
Q-balls with arbitrarily small charge, no matter how weak gravity is. That is,
gravity saves Q-balls with small charge. We also show how stability of Q-balls
changes as gravity becomes strong.

15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
16
The categories of this paper are: stat