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Boson Stars in a Theory of Complex Scalar Field coupled to Gravity

We study boson stars in a theory of complex scalar field coupled to Einstein gravity with the potential: $V(|Φ|) := m^{2} |Φ|^2 +2 λ|Φ|$ (where $m^2$ and $λ$ are positive constant parameters). This could be considered either as a theory of massive complex scalar field coupled to gravity in a conical potential or as a theory in the presence of a potential which is an overlap of a parabolic and a conical potential. We study our theory with positive as well as negative values of the cosmological constant $Λ$. Boson stars are found to come in two types, having either ball-like or shell-like charge density. We have studied the properties of these solutions and have also determined their domains of existence for some specific values of the parameters of the theory. Similar solutions have also been obtained by Hartmann, Kleihaus, Kunz, and Schaffer, in a V-shaped scalar potential.