Los Alamos National Labs with logo 2021

Theoretical Division

Theoretical research encompasses all disciplines of science.
  • Physics and chemistry of materials

  • Nuclear and particle physics, astrophysics, and cosmology

  • Fluid dynamics and solid mechanics

  • Physics of condensed matter and complex systems

  • Applied mathematics and plasma physics

  • Theoretical biology and biophysics

  • Division Leader (acting)
  • James Colgan
  • Email
  • Deputy Division Leader (acting)
  • Enrique Batista
  • Email
  • Staff Operations Manager
  • Danielle Bergemann
  • Email

Furthering knowledge of the physical world for national security

Our strong interdisciplinary teaming and unique research facilities allow us to develop solutions to complex problems, and to support partners and collaborators, all with the goal of strengthening national security and making a safer world.

Why our theory research matters

At Los Alamos, theoretical work is a combination of basic research and applications, with each aiding the other in making progress. Theory is the backbone of all sciences. Theories have multiple roles to play in the furtherance of knowledge including:

  • explaining what is already known
  • predicting what will happen in unknown situations
  • providing foundations for furthering scientific knowledge

Theoretical research encompasses all disciplines of science and ranges from fundamental issues to the modeling of complex systems. Theoretical results contribute to computer modeling, and the tests and applications that result from modeling help define new directions in basic research.


Marianne Francois

Dr. Marianne Francois is currently the division leader of the Theoretical Division at Los Alamos National Laboratory (LANL). The division delivers fundamental and applied science for various DOE programs. Prior to becoming division leader, Francois was the program manager for Physics and Engineering Model for the NNSA Advanced Simulation and Computing (ASC) program (2018-2020), the Group Leader of the Methods and Algorithms Group in the X-Computational Physics Division (2015-2018), the Deputy Group Leader of the Fluid Dynamics and Solid Mechanics Group (T-3) in the Theoretical Division (2012-2015), a scientist (2005-2012) and postdoc (2002-2004) in the Computer, Computational and Statistical Sciences Division.

Francois is a recognized expert in computational fluid dynamics, multiphase and multi-materials flows, heat transfer, materials processing and the associated numerical methods. She has solved problems across a spectrum of open science and national security applications. Her expertise and leadership skills have led her to make critical scientific and technical contributions to the NNSA and the broader DOE mission. She has been the lead for the National Security Applications within the DOE Exascale Computing Project.

Francois is a Fellow of the American Society of Mechanical Engineers (ASME) and a Fellow of the DOE Oppenheimer Science and Energy Leadership Program. She received her PhD in Aerospace Engineering from the University of Florida in 2002, her Master of Science in Aerospace Engineering from Embry-Riddle Aeronautical University in 1998, and her Diplome d’Ingenieur in Engineering Physics from EPF in France in 1997.

James Colgan

Dr. James Colgan is the deputy division leader of Theoretical Division. Prior to this role, James was Group Leader of the Physics and Chemistry of Materials (T-1) group from 2017 to 2022 and also served as Acting Deputy Division Leader for 5 months in 2019-2020.

Colgan received his BSc (1996) and PhD (2000) degrees in Theoretical Physics from Queen’s University, Belfast, Northern Ireland. After a post-doctoral position at Auburn University, he joined LANL in 2003 as a post-doctoral researcher and was converted to a staff scientist position in 2005 in Theoretical Division.

Colgan has more than 20 years of research experience in atomic, molecular and plasma physics. He has published around 200 research papers in these areas and was elected a Fellow of the American Physical Society (APS) in 2012 and a Fellow of the U.K. Institute of Physics (IOP) in 2021. His research interests are in atomic and molecular collision physics, atomic processes in plasmas, and modeling a variety of laser-produced plasmas. In the 2010s, he led work to produce a new generation of Los Alamos opacity tables and has recently worked on producing a new air opacity table.

  • Applied Mathematics
  • Chemistry
  • Biology
  • Engineering
  • Materials
  • Theoretical Physics
  • Physics and Chemistry of Materials
  • Nuclear and Particle Physics, Astrophysics, and Cosmology
  • Fluid Dynamics and Solid Mechanics
  • Physics of Condensed Matter and Complex Systems
  • Applied Mathematics and Plasma Physics
  • Theoretical Biology and Biophysics
Core strategies, programs

To accomplish its national security mission, the Laboratory has assembled the components of a core expertise by integrating theory, modeling, simulation, and visualization. It is a bold strategy to provide new cutting-edge tools to interpret and guide experiments and to further the fundamental understanding of and predictive capabilities for complex phenomena.

The science-based Stockpile Stewardship Program—the centerpiece of the Department of Energy Weapons Complex—depends critically on the viability of this strategy. However, its applicability extends well beyond the stewardship program; in fact, virtually every major initiative at the Laboratory relies heavily, if not critically, on this integrated capability.

The coupling of computational simulations and experiments as a cornerstone of technical programs in

  • weapons,
  • threat reduction
  • biology
  • nanomaterials
  • energy
  • infrastructure
  • frontier science

requires a new generation of ideas and concepts to greatly improve the fidelity, reliability, certainty, and usability of these tools.