A Possible Origin of Dark Energy

We discuss the possibility that the existence of dark energy may be due to the presence of a spin zero field $\phi(x)$, either elementary or composite. In the presence of other matter field, the transformation $\phi(x)\to \phi(x) +$ constant can generate a negative pressure, like the cosmological constant. In this picture, our universe can be thought as a very large bag, similar to the much smaller MIT bag model for a single nucleon.Comment: 4 pages, no figure, typos correcte

Jarlskog Invariant of the Neutrino Mapping Matrix

The Jarlskog Invariant $J_{\nu-map}$ of the neutrino mapping matrix is calculated based on a phenomenological model which relates the smallness of light lepton masses $m_e$ and $m_1$ (of $\nu_1$) with the smallness of $T$ violation. For small $T$ violating phase $\chi_l$ in the lepton sector, $J_{\nu-map}$ is proportional to $\chi_l$, but $m_e$ and $m_1$ are proportional to $\chi_l^2$. This leads to $J_{\nu-map} \cong {1/6}\sqrt{\frac{m_e}{m_\mu}}+O \bigg(\sqrt{\frac{m_em_\mu}{m_\tau^2}}\bigg)+O \bigg(\sqrt{\frac{m_1m_2}{m_3^2}}\bigg)$. Assuming $\sqrt{\frac{m_1m_2}{m_3^2}}<<\sqrt{\frac{m_e}{m_\mu}}$, we find $J_{\nu-map}\cong 1.16\times 10^{-2}$, consistent with the present experimental data.Comment: 19 page

Domain walls on the surface of q-stars

We study domain-wall networks on the surface of q-stars in asymptotically flat or anti de Sitter spacetime. We provide numerical solutions for the whole phase space of the stable field configurations and find that the mass, radius and particle number of the star is larger but the scalar field, responsible for the formation of the soliton, acquires smaller values when a domain-wall network is entrapped on the star surface.Comment: 11 pages, 6 figures, to appear in Jurn. Math. Phy