How does gravity save or kill Q-balls?

الأصل · EN

We explore stability of gravitating Q-balls with potential V₄(ϕ)=m²2ϕ²-λϕ⁴+ϕ⁶/M² via catastrophe theory, as an extension of our previous work on Q-balls with potential V₃(ϕ)=m²2ϕ²-μϕ³+λϕ⁴. In flat spacetime Q-balls with V₄ in the thick-wall limit are unstable and there is a minimum charge Q min, where Q-balls with Q<Q 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.