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Los Alamos Distinguished Postdoc Fellows

Meet the Lab's Current Distinguished Postdoctoral Fellows

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Los Alamos Distinguished Postdoctoral Fellows (pdf)

Lauren J. Beesley

Feynman Distinguished Postdoctoral Fellow
Analytics, Intelligence and Technology Division: Information Systems and Modeling (A-1)
Computer, Computational and Statistical Sciences Division: Statistical Sciences (CCS-6)

beesley.jpgEducation: Ph.D. in Biostatistics - University of Michigan; B.S. in Mathematics - University of Kansas

Mentors: Sara Del Valle and Davis Osthus

Research: Lauren’s research addresses statistical challenges that arise during analysis of complex observational data, including handling of missing data, variable selection, measurement error, and selection bias. Lauren has collaborated with researchers across a variety of scientific domains, including oncologists and medical doctors, epidemiologists, human geneticists, computer scientists, biologists, and mathematicians. At LANL, Lauren’s research will focus on the common setting where researchers want to develop prediction models based on multiple different data streams (e.g., social media, satellite imagery, demographics, etc.). Data quality can vary substantially between different data sources, and issues such as missing data, measurement error, and massive data size all pose unique and consequential challenges. Lauren’s research will work to address some of these challenges, with the ultimate goal of giving better model predictions. Lauren’s work will center on two key applications, including forecasting of political instability across various spatial resolutions and addressing problems with data quality and backfill in prediction modeling of influenza outbreaks. 

Bio: Lauren received her PhD in Biostatistics under the mentorship of Dr. Jeremy M G Taylor at The University of Michigan. Her dissertation research focused on handling of missing data for complicated event time outcomes, with a particular emphasis on risk prediction for survival and recurrence outcomes for patients diagnosed with cancer. After her PhD, Lauren worked with Dr. Bhramar Mukherjee as a Postdoctoral Research Fellow at The University of Michigan, where she developed statistical strategies for reducing bias due to selection and measurement error in health research using electronic health record data. In her free time, Lauren enjoys cooking/baking and crafting.


Joshua Burby

Feynman Distinguished Postdoctoral Fellow
Theoretical Division: Applied Mathematics and Plasma Physics (T-5)

burby.jpgEducation:Ph.D. in Plasma Physics - Princeton University; B.S. in Engineering Physics - Cornell University

Mentors: Xianzhu Tang and Luis Chacon

Research: Josh's research aims to efficiently model the intricate multiscale properties of plasmas using tools from dynamical systems theory and differential geometry. He focuses on developing broadly-applicable analytic and computational techniques for coping with the time- and space-scale separation associated with stiff plasma dynamics. Through his research, Josh recognized that phase-space-geometric objects known as slow manifolds appear and play a foundational role in a variety of reduced models for multiscale plasma behavior. Notably, he used this observation to explain how those models inherit Hamiltonian structure from more-complete descriptions of the plasma state. As he continues to explore the ramifications of slow manifolds in plasma physics, Josh is developing "slow manifold integrators" at LANL. These are simulation algorithms that use a system's slow manifold to solve the preconditioning problem inherent to implicit simulations of temporally-stiff systems.

Bio: Josh earned his PHD under the mentorship of Professor Hong Qin at the Princeton Plasma Physics Laboratory. Being more of a mathematical physicist than a traditional theoretical physicist, Josh spent his first postdoc at the Courant Institute of Mathematical Sciences as a DOE Fusion Energy Sciences (FES) Fellow. After leaving Courant and before coming to LANL, he joined the Mathematical Sciences Research Institute (MSRI) as a Viterbi Fellow during the program "Hamiltonian systems, from topology to applications through analysis."


Carl Fields

Oppenheimer Distinguished Postdoctoral Fellow
Computer, Computational and Statistical Sciences Division: Computational Physics and Methods (CCS-2)
Theoretical Division: Applied Mathematics and Plasma Physics (T-5)
Computational Physics Division: Eularian Codes (XCP-2)


fields.jpgEducation: Ph.D. Michigan State University - Astronomy and Astrophysics; B.S. Arizona State University - Physics and Astrophysics

Mentors: Joshua Dolence, Wesley Even and Samuel Jones

Research: Carl's research focuses core-collapse supernova explosions and their massive star progenitors, stellar evolution and nucleosynthesis, and astrophysical sources of gravitational waves. He works on developing state-of-the-art computational and numerical methods for hydrodynamic simulations. These hydrodynamic models can directly impact the qualitative properties of massive stars and their stellar explosions. Stellar explosions can produce multi-messenger signals capable of being detected by current and next-generation astrophysical observations. Groundbreaking observational efforts, such as the LIGO observatory and the Super-K neutrino detector, benefit directly from our work. At LANL, Carl will be involved in ongoing development of next-generation large-scale computational tools capable of utilizing exa-scale machines to answer some of the largest questions of our Universe.

Bio: Carl earned his PhD working with Professor Sean Couch. He was supported by a National Science Foundation Graduate Research Fellowship and a FORD Foundation Predoctoral Fellowship during his time at MSU. In December 2020, Carl was named to the prestigious Forbes 30 Under 30 for Science list. In the fall of 2020, He was awarded the Dr. Pliny A. and Margaret H. Price Prize recognizing research excellence and exceptional promise in areas related to Ohio State University Center for Cosmology and Astroparticle Physics initiatives. Fields was also named to the Inaugural class of the Edward A. Bouchet Graduate Honor Society chapter at MSU in 2019. For his B.S., he worked with Professor Frank Timmes on stellar evolution models.  


 Ronen Weiss

Oppenheimer Distinguished Postdoctoral Fellow
Theoretical Division: Nuclear and Particle Physics, Astrophysics and Cosmology (T-2)

weiss.jpgEducation: Ph.D. and M.S. in Physics and B.S. in Physics and Mathematics - Hebrew University of Jerusalem

Mentors: Joseph Carlson, Vincenzo Cirigliano and Stefano Gandolfi

Research: The focus of Ronen's research work is the study of nuclear short-range correlations, i.e. the effects resulting from few nucleons (protons and neutrons) coming very close to each other. Understanding the short-range structure of nuclei is important for gaining a full description of nuclear systems. During his PhD studies, Ronen developed the generalized contact formalism (GCF), which provides a coherent picture of the dynamics of two-body nuclear short-range correlations and enables quantifying their effects on various nuclear quantities. Using the GCF it is possible to directly compare ab-initio structure calculations and the underlying nucleon-nucleon interaction with electron-scattering data. Ronen's work had a significant impact in the field and the GCF is now implemented as an important tool used directly by leading experimental groups. At LANL, Ronen will work on making the GCF into a systematic expansion, including the description of the elusive correlated triplets. With such a progress, it will be possible to use the GCF to provide predictions regarding broad aspects of nuclear systems, including neutrinoless double beta decay and neutrino scattering.

Bio: Ronen completed his PhD under the mentorship of Professor Nir Barnea. Ronen was the first student in the local research group to study the field of short-range correlations, and as a result it has become one of the main topics studied in this group. In his research work, Ronen has collaborated with leading world-wide experts, both theoreticians and experimentalists. He was awarded several prizes and scholarships for his achievements in research, including the Racah prize of the Israel Physical Society, the Clore scholarship, Wolf scholarship and the Pazy foundation prize for PhD students, the Goodman prize of the Racah Institute in the Hebrew University. Along with his research, Ronen also enjoyed his work as a teaching assistant in the physics lab and electricity and magnetism courses for undergraduate students, for which he was also awarded an excellence prize.