Symmetry Energy from Holographic QCD

We review the symmetry energy in the context of AdS/CFT correspondence. After constructing $D$ brane configurations corresponding to dense system in boundary theory, we calculate the symmetry energy by solving DBI action of $D$ branes in confining and deconfining phase. We conclude the density dependence of the symmetry energy has scaling law whose power depends only on dimensionality of the branes and space-time.Comment: 9 pages, 5 figures. Some compile errors are corrected. arXiv admin note: substantial text overlap with arXiv:1201.045

Viscoelastic modulus reconstruction using time harmonic vibrations

This paper presents a new iterative reconstruction method to provide high-resolution images of shear modulus and viscosity via the internal measurement of displacement fields in tissues. To solve the inverse problem, we compute the Fr\'echet derivatives of the least-squares discrepancy functional with respect to the shear modulus and shear viscosity. The proposed iterative reconstruction method using this Fr\'echet derivative does not require any differentiation of the displacement data for the full isotropic linearly viscoelastic model, whereas the standard reconstruction methods require at least double differentiation. Because the minimization problem is ill-posed and highly nonlinear, this adjoint-based optimization method needs a very well-matched initial guess. We find a good initial guess. For a well-matched initial guess, numerical experiments show that the proposed method considerably improves the quality of the reconstructed viscoelastic images.Comment: 15 page