Computational Engineer, Computational Engineering Division, Lawrence Livermore National Laboratory, 2011–present
Postdoc, Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, 2009
Postdoc, Earth and Planetary Science, University of California Berkeley, 2008
Ph.D., Computational Condensed Matter Physics, University of Illinois at Urbana-Champaign, 2007
Computational Science and Engineering certificate, University of Illinois at Urbana-Champaign, 2007
I developed first principles quantum Monte Carlo methods to simulate helium and hydrogen superfluid properties. My graduate work explained the supersolid-like behavior of helium and the occurrence of magic numbers in small superfluid hydrogen clusters. As a postdoc at UC Berkeley, I presented work in favor of the helium rain hypothesis inside Jovian planets. During my second postdoc experience at LLNL, I co-developed a path integral Monte Carlo code that calculates the hydrogen Hugoniot that agrees with an existing set of experiments and provides predictions over a warm, dense region inaccessible to experiments. I also helped validate results in the Cimarron project on dense and strongly coupled plasma. Currently, I am a code physicist working in the ALE3D team on energy conservation in shocks and on additive manufacturing.
Computational method development and analysis in the following: Arbitrary Lagrangian-Eulerian techniques for multiphysics hydrodynamics (ALE3D code); mesoscale simulation of the physical processes in selective laser melting of powder; classical and quantum Monte Carlo methods (Path Integral, Diffusion, Variational, Kinetic, etc.); equation-of-state of materials at extreme conditions from first-principle methods; density functional theory calculations of electronic structure (Abinit VASP and CASINO codes); plasma physics; classical and quantum molecular dynamics (Qbox code).
Khairallah, S. A. and Anderson, A., “Mesoscopic Simulation Model of Selective Laser Melting of Stainless Steel Powder,” Journal of Materials Processing Technology, DOI. 10.1016/j.jmatprotec.2014.06.001 (in press).
Lorin X. Benedict, Michael P. Surh, John I. Castor, Saad A. Khairallah, Heather D. Whitley, David F. Richards, James N. Glosli, Michael S. Murillo, Christian R. Scullard, Paul E. Grabowski, David Michta, and Frank R. Graziani, “Molecular dynamics simulations and generalized Lenard-Balescu calculations of electron-ion temperature equilibration in plasmas,” Phys. Rev. E86, 046406 (2012).
Graziani, F. R., Batista, V. S., Benedict, L. X., Castor, J. I., Chen, H., Chen, S.N., Fichtl, C.A., Glosli, J. N., Grabowski, P. E., Graf, A. T. Hau-Riege, S. P., Hazi, A. U. Khairallah, S. A., Krauss, L., Langdon, A. B., London, R. A., Markmann, A., Murillo, M. S., Richards, D. F., Scott, H. A., Shepherd, R., Stanton, L. G., Streitz, F. H., Surh, M. P., Weisheit, J. C., and Whitley, H. D., “Large-scale molecular dynamics simulation of dense plasmas: The Cimarron Project,” High Energy Density Physics8, 105–131 (2012).
S. A. Khairallah, J. Shumway, E. W. Draeger, “Path Integral Calculations of the Hydrogen Hugoniot Using Augmented Nodes”, arXiv:1108.1711v1 cond-mat, http://arxiv.org/abs/1108.1711 (2011).
S. A. Khairallah, Burkhard Militzer, “First-Principles Studies of the Metallization and the Equation of State of Solid Helium,” Phys. Rev. Lett.101, 106407 (2008).
S. A. Khairallah, M. B. Sevryuk, D. M. Ceperley, and P. Toennies, “Interplay between Magic Number Stabilities and Superfluidity of Small Parahydrogen Clusters,” Phys. Rev. Lett.98, 183401 (2007).