Mass loss and longevity of gravitationally bound oscillating scalar lumps (oscillatons) inDdimensions

Abstract

Spherically symmetric oscillatons (also referred to as oscillating soliton stars) i.e. gravitationally bound oscillating scalar lumps are considered in theories containing a massive self-interacting real scalar field coupled to Einstein's gravity in 1 + D dimensional spacetimes. Oscillations are known to decay by emitting scalar radiation with a characteristic time scale which is, however, extremely long, it can be comparable even to the lifetime of our universe. In the limit when the central density (or amplitude) of the oscillaton tends to zero (small-amplitude limit) a method is introduced to compute the transcendentally small amplitude of the outgoing waves. The results are illustrated in detail on the simplest case, a single massive free scalar field coupled to gravity.

Dynamical Boson Stars

“…Therefore, the truncated solutions constructed above are not exactly time periodic. Indeed, very accurate numerical work has shown that the oscillatons radiate scalar field on extremely long time scales while their frequency increases [84, 97]. This work finds a mass loss rate of just one part in 10 12 per oscillation period, much too small for most numerical simulations to observe.…”

“…[84] considers oscillatons in higher dimensions and measure the scalar mass loss rate for dimensions 3, 4, and 5. They extend this work considering inflationary spacetimes [83].…”

Gravipulsons

“…While the stability analysis is out of the scope of the present work, it is worth noting that the stability of the solution (9), and hence (11), is determined by the stability of the solutions of the nonhomogeneous Hill's equation X n ðÞ involved in (16). In turn, as it follows from (24), the stability of the general solution X n ðÞ is determined by the behavior of the functions X þ n ðÞ and X À n ðÞ. It is clear that all solutions X n ðÞ satisfying the initial conditions (33) and (34) are unstable in the resonance case n > 0.…”

“…1, we substitute (22) and (23) into (24) and require that X n ðÞ ¼ X n ð þ TÞ. In this equality the integrals between the limits 0 and cancel out.…”

“…Recently, in Ref. [24] small amplitude pulson solutions of the EKG system have been obtained for the potentials expansible in a power series. This brings up the following question: How does gravity affect the dynamics of the finite amplitude pulsons?…”