Current Lawrence Postdoctoral Fellows


Amanda Randles

Ph.D. in Earth and Planetary Sciences from Harvard University
Joined the PLS Division in 2013

Research: Amanda's research focuses on the investigation of fundamental questions related to computational fluid mechanics as well as the development of multiscale models to study biomedical applications. One such target is to model blood flow through patient-specific arterial geometries. The goal of this project is to provide conceptual insight into the prediction of secondary cancer site locations and the underlying mechanics driving cancer metastasis. She will carry out large circulatory models to investigate the ability of computation to aid in disease prediction and diagnosis. The scale and scope of these simulations requires the use of high performance supercomputers, so much of her work will focus on the study of methods to improve the parallel performance of the fluid models.

Bio: Amanda Randles is a Lawrence Postdoctoral Fellow working in the Center for Applied Scientific Computing at LLNL. Working with Professors Efthimios Kaxiras and Hanspeter Pfister, she completed her Ph.D. in Applied Physics at Harvard University with a secondary field in Computational Science in 2013. In 2010 she obtained her Master's Degree in Computer Science from Harvard University. Prior to graduate school, she worked for three years as a software developer at IBM on the Blue Gene Development Team. Her primary roles were in application development and performance analysis. She received her Bachelor's Degree in both Computer Science and Physics from Duke University.


Richard Kraus

Ph.D. in Earth and Planetary Sciences from Harvard University
Joined the PLS Division in 2013

Research: I use various dynamic compression techniques to learn about the rheology and thermodynamic properties of materials at conditions relevant to hypervelocity impacts, planetary interiors, and ICF. I then use the acquired data to constrain and validate models for use in numerical simulations.

Bio: Richard Kraus is a Lawrence Postdoctoral Fellow at LLNL. He received his undergraduate degree in Physics at the University of Nevada, Reno. In 2008 he received an MPhil in Physics from the University of Cambridge, UK and in 2013 he received his M.S. in Applied Physics and PhD in Earth and Planetary Sciences from Harvard University. His thesis research was on the thermodynamics of planetary impact events with a focus on impact induced vaporization.


Brenda Rubenstein

Ph.D. in Chemical Physics from Columbia University
Joined the PLS/CMMD Division in 2013

Research: Brenda's research revolves around developing novel quantum Monte Carlo techniques capable of studying systems in which quantum statistics assume a pivotal role. Over the past few decades, a number of mean field theory-based techniques, Density Functional Theory (DFt) chief among them, have grown exceedingly popular as economical ways of determining the properties of quantum materials. Despite their popularity -- and success, these techniques often trade accuracy for computational efficiency. In contrast, quantum Monte Carlo techniques promise much higher levels of accuracy for only a modest increase in computational cost. Brenda's research aims to develop the theoretical and algorithmic tools necessary for making quantum Monte Carlo a practical option for many electronic structure, low-temperature, and/or high-pressure calculations. While at the lab, Brenda hopes to apply the algorithms she develops to the study of hydrogen plasmas and the actinides.

Bio: Brenda Rubenstein is currently a Lawrence Fellow working in the Quantum Simulations Group at LLNL. Brenda obtained her Sci.B. in Chemical Physics from Brown University in 2007, after which she received a Churchill Fellowship to study at the University of Cambridge. Upon completing her M.Phil. in Theoretical Chemistry at Cambridge in 2008, she moved to Columbia University to pursue her Ph.D. in Chemical Physics under the tutelage of Prof. David Reichman. During her Ph.D., she frequently collaborated with researchers both at Lawrence Livermore and Los Alamos as part of her DOE Computational Science Graduate Fellowship. After completing her Ph.D. in 2013, she immediately moved into her current position at Lawrence Livermore.

Anne Dekas

Ph.D. in Geological and Planetary Sciences, Geobiology, from the California Institute of Technology
Joined the Physical and Life Sciences Directorate in 2013

Research: I am interested in the chemical reactions microbes catalyze, and how these conversions affect the chemistry and climate of our planet. My specific interests include microbial metabolisms (particularly nitrogen fixation, anaerobic methane oxidation, methanogenesis, sulfate reduction, and ammonia oxidation), biogeochemical cycling of carbon and nitrogen, marine microbial ecology (including methane seeps and hydrothermal vents), microbial symbiosis, the distribution and metabolic flexibility of the Archaea, microbe-mineral interactions, stable isotope probing, and developing techniques to investigate microbial activity within complex environments.

Bio: Anne Dekas is a Lawrence Postdoctoral Fellow at LLNL in the Chemical Sciences Division. She completed her Ph.D. in the laboratory of Victoria Orphan at the California Institute of Technology in the Division of Geological and Planetary Sciences (2012). She obtained a Bachelor’s degree from the Earth and Planetary Science Department at Harvard University, with a specialty in biogeochemistry (2004). Originally interested in space sciences, Anne has performed research at three NASA centers (Goddard Space Flight Center, summer 2002; Ames Research Center, summer 2003; and the Jet Propulsion Laboratory, 2005-2006) and continues to be interested in Astrobiology and studying life in extreme environments.

Frederico Fiuza

Ph.D. in Plasma Physics from Instituto Superior Tecnico, Portugal
Joined the Physical and Life Sciences Directorate in 2012

Research: I use massively parallel particle-in-cell simulations and plasma theory to understand the physics behind intense laser/beam-plasma interactions of relevance for inertial confinement fusion, novel radiation sources, astrophysical shocks, and particle acceleration for medical applications.

Bio: Frederico Fiuza is a Lawrence Postdoctoral Fellow at LLNL. He received his Masters degree in Physics and his PhD degree in Plasma Physics from Instituto Superior Tecnico (IST, Portugal) in 2007 and 2012, respectively. Between 2004 and 2012 he conducted his research at the Group of Lasers and Plasmas (IST) under the supervision of Luis Silva. During 2009, he was also a visiting scholar at the Plasma Simulation Group (UCLA) under the supervision of Warren Mori. Frederico has more than 30 publications in peer-reviewed journals and he has been awarded the Oscar Buneman Award for Best Visualization of Plasmas in 2011.


Brad Pollock

Ph.D. in Engineering Sciences from University of California, San Diego
Joined the NIF Directorate in 2012

Research: The interaction of ultra-short laser pulses with underdense plasmas provides a platform for compact, high energy electron acceleration. With accelerating fields of ~1 GeV/cm, these devices (known as laser wakefield accelerators) have demonstrated electron beam energies exceeding 2 GeV in less than 10 cm, with plans to achieve 10 GeV electron beams in the next few years. This technique brings high energy electron and radiation research to a compact scale accessible to universities, hospitals, and industry.

Bio: Brad Pollock first joined LLNL as an undergraduate student in the summer of 2005. After finishing his bachelor's degree in 2006, he returned to the lab as a graduate student and became a Lawrence Scholar in 2008 while pursuing his Ph. D. from UC San Diego. Brad's research in the field of laser wakefield acceleration led to a first-author publication in Physical Review Letters and multiple presentations at conferences and workshops. Brad began his Lawrence Fellowship upon graduating from UCSD in May 2012, and is currently located in the NIF and PS directorate in the plasma physics group led by Siegfried Glenzer. While his main research topic remains wakefield acceleration, Brad is also interested in high energy density science, inertial confinement fusion, and magnetized plasma research.


S. Mark Ammons

Ph.D. in Astrophysics from University of California, Santa Cruz
Joined the PLS/Physics Division in 2011

Research: Mark develops technologies for turbulence compensation in propagated light, including adaptive optics, and exploits these in telescopes for improved astrophysical observations. In particular, he is exploring Multi-Conjugate Adaptive Optics in astronomy for wide-field, diffraction-limited imaging and detection of exoplanets via astrometric motion. With collaborators at the University of Arizona, he is also searching for the most massive clusters of galaxies in the universe. At LLNL, he is studying adaptive optics for imaging and surveillance applications.

Bio: Mark is a Lawrence Postdoctoral Fellow at LLNL. He completed his PhD under Claire Max and David Koo at UC Santa Cruz in 2009. He joined the Laboratory in 2011 after visiting the University of Arizona with a NASA Hubble Fellowship in 2009-2010. He has 27 publications related to adaptive optics and astronomical instrumentation and 14 publications in astrophysics. Mark has been the recent recipient of several research fellowships and has been involved in adaptive optics for 11 years.

Website: www.u.arizona.edu/~ammons81

Previous Lawrence Fellowship Recipients

Year Name Ph.D. Institution
2013 Richard Kraus Harvard University
Brenda Rubenstein Columbia University
Amanda Randles Harvard University
2012 Frederico Fiuza Instituto Superior Tecnico, Portugal
Bradley Pollock University of California, San Diego
2011 Jeremy Mason Massachusetts Institute of Technology
Jimin Yu University of Cambridge
2010 Celia Reina Romo California Institute of Technology
2009 Mark Ammons University of California, Santa Cruz
Yosuke Kanai Princeton University
Andrea Kritcher University of California, Berkeley
Joshua White Stanford University
2008 Alfredo Correa-Tedesco University of California, Berkeley
Ming Tang Massachusetts Institute of Technology
2007 Gang Logan Liu University of California, Berkeley
Peter Pauzauskie University of California, Berkeley
2006 Grigory Bronevetsky Cornell University
Nadeen Chahine Columbia University
Aleksandar Donev Princeton University
Nicholas Scielzo University of California, Berkeley
2005 Jung-Fu Lin University of Chicago
David Lobell Stanford University
Vincenzo Lordi Stanford University
2004 Jason Raymond Arizona State University
Evan Reed Massachusetts Institute of Technology
2003 Yu Huang Harvard University
Yuan Ping Princeton University
2002 Sergei Kucheyev Australian National University
Diego Torres Universidad Nacional de La Plata
2001 Wei Cai Massachusetts Institute of Technology
Kenneth Kim University of California, Berkeley
Christopher Schuh Northwestern University
2000 Olgica Bakajin Princeton University
Julio Camarero Universitat de Barcelona
1999 Shea Gardner University of California, Davis
Jeffrey Grossman University of Illinois at Urbana-Champaign
Luc Machiels École Polytechnique Fédérale de Lausanne
Andrew Williamson University of Cambridge
1998 Nicolas Hadjiconstantinou Massachusetts Institute of Technology
Robert Heeter Princeton University
Aleksandr Noy Harvard University
Joel Ullom Harvard University