13,915 research outputs found
Symmetry Energy from Holographic QCD
We review the symmetry energy in the context of AdS/CFT correspondence. After
constructing brane configurations corresponding to dense system in boundary
theory, we calculate the symmetry energy by solving DBI action of 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
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