Theory Research Group

This group studies the foundations, techniques, and applications of relativity, quantum, and information theory. We develop numerical, algebraic, and analytic approaches to understand complex problems. Current projects include mergers of and energetic emissions from compact objects in general relativity; critical phenomena in nonlinear field theories; coherent behavior in dynamical systems; interaction between radiation and matter; molecular dynamics of defects and impurities in clusters and solids; spin systems and quantum entanglement. Our computational resources include extensive supercomputing facilities on campus and allocations at national supercomputing centers.

See the Theoretical and Mathematical Research Group Website for further information.

Group Meetings

Title Time Day Room
Theory Group Seminar 3 pm Tu N209

Theory Faculty Members

Gus Hart

Gus Hart
Gus Hart

Research Specialty: Machine Learning, Modeling and Simulation, Biophysics

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Research Projects

  • Image AI for bacterial tomograms

    We are developing AI to identify nanostructures inside of bacteria. In collaboration with Grant Jensen's lab (who has about 40,000 images taken over 20 years) we are working to understand basic life processes. Our focus includes some "standard" computer vision methods as well as new methods based on neural networks, transformers, etc. We also collaborate with Bryan Morse's lab in CS.

    Suggested Preparation:

    A work ethic, excitement for research, the ability to balance research and homework, enthusiasm for new things, the desire to contribute positively to a team. Programming and software skills or the desire to develop them. Enthusiasm for math and more math.

    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students

Eric Hirschmann

Eric Hirschmann
Eric Hirschmann

Research Specialty: General relativity, nonlinear field theories, computational physics

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Research Projects

  • General relativistic compact binaries

    We are interested in all aspects of compact object binary mergers (black holes and neutron stars).  This includes predicting the gravitational and electromagnetic radiation from such systems as well as constraining the properties of dense matter in such mergers.

    This work involves large scale computation and necessitates developing numerical algorithms for solving the nonlinear partial differential equations of general relativity and radiation magnetohydrodynamics.   

    Suggested Preparation:

    Suitable for
    • Undergraduate students
    • Graduate students
  • Relativistic magnetohydrodynamics

    Past, present and future projects include

    1.   Establishing the characteristic structure of the equations of general relativistic magnetohydrodynamics (GRMHD) in different formulations.
    2.   Studying the instabilities and waves associated with this system in different geometries.  
    3.   Developing constraint preserving boundary conditions for GRMHD.
    4.   Developing simulations in 1D, 2D and 3D for flat space MHD.  
    Suitable for
    • Undergraduate students
    • Graduate students
  • General relativisitic equilibrium models of magnetars

    We would like to construct axisymmetric, general relativistic, equilibrium models of neutron stars with ultra-strong magnetic fields (magnetars).  Physics inputs include poloidal and toroidal magnetic fields, realistic equations of state for the matter, differential rotation and convective motions.  

    Suitable for
    • Undergraduate students
    • Graduate students
  • Charged black holes in higher dimensions
    The Kerr-Newman black hole is the charged, rotating black hole in 4 dimensions.  The 5 dimensional version is not known.  Using numerical techniques we are trying to construct it.  
    Suitable for
    • Undergraduate students
    • Graduate students

David Neilsen

David Neilsen
David Neilsen

Research Specialty: General relativity; relativistic astrophysics; fluid dynamics; parallel computing

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Research Projects

  • General Relativity
    General relativity describes gravitational phenomena geometrically as curvature in spacetime: Matter curves space, and the spacetime curvature affects matter. General relativity predicts that accelerating objects can emit gravitational radiation. While this radiation is typically extremely weak, some astrophysical systems, such as colliding black holes or neutron stars, may emit gravitational waves that we can detect on Earth. Large, kilometer scale laser interferometers, such as LIGO, are being constructed to study gravitational wave signals from these events. Unfortunately, we currently know very little about the radiation expected from the regions of spacetime with the strongest (nonlinear) gravitational fields. I study computational methods for solving the Einstein equations for these strong-field gravitational wave sources. Various projects are available to investigate black hole spacetimes, black hole formation, and properties of the Einstein equations. All projects require writing, testing, and running computer codes to investigate nonlinear gravitational phenomena.
    Suggested Preparation: Students should plan on spending a significant amount of time learning the fundamentals of general relativity, tensor analysis and computational methods as part of their research.
    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students
  • Relativistic fluid dynamics (RFD)
    Neutron star collapse, supernovae, gamma-ray sources, etc., are some of the exciting topics in relativistic astrophysics, and the perfect fluid is the fundamental model for all of these. I study relativistic perfect fluids near black holes using computational methods. In particular, Eric Hirschmann, Steven Millward and I at BYU are studying a magnetized fluid around a black hole with computational Magneto-Hydrodynamics (MHD). Various computational projects are available in RFD and MHD, which require writing, testing and running computer programs to model relativistic fluids.
    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students
  • Numerical methods
    Research with the Einstein equations and RFD requires sophisticated numerical methods and techniques (as well as cheats and tricks). Some techniques include adaptive mesh refinement (AMR), parallel computing, high-resolution shock-capturing methods for fluid equations. Some systems, such as moving black holes, may naturally be solved in multiple reference frames simultaneously. I am investigating the use of overlapping computational grids for these problems. One particular interest is combining modern fluid methods with overlapping grids.
    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students

Jean-Francois Van Huele

Jean-Francois Van Huele
Jean-Francois Van Huele

Research Specialty: all aspects of quantum theory, especially quantum dynamics and quantum information

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Research Projects

  • Quantum Dynamics

    Study of time evolution of quantum systems, in particular simple quantum optical systems. We are also interested in quantum clocks and their precision.  The project welcomes new students. Motivation is more important than previous experience, although knowledge of linear algebra, Mathematica, and modern physics will definitely help.

    Suitable for
    • Undergraduate students
    • REU students
  • Quantum Information

    Studies in entanglement, uncertainties, noise, and measurement. Applications include teleportation, cloning, and quantum algorithms, The project welcomes new students. Motivation is more important than previous experience, although knowledge of linear algebra, Mathematica, and modern physics will definitely help. 

    Suitable for
    • Undergraduate students
    • REU students
  • Quantum Thermodynamics

    How does thermodynamics, which traditionally studies concepts like work, heat, and entropy integrate fluctuations and new quantum resources like entanglement into its formalism? We are studying thermal machines, such as the Szilard engine in the quantum regime to probe the validity and compatibility of thermal physics, information theory and quantum theory. The project welcomes new students. Motivation is more important than previous experience, although knowledge of linear algebra, Mathematica, thermodynamics and modern physics will definitely help.   

    Suitable for

Chris Verhaaren

Chris Verhaaren
Chris Verhaaren

Research Specialty: High Energy Theory; Particle Theory; Particle Phenomenology; Quantum Field Theory

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Research Projects

  • Beyond the Standard Model phenomenology

    Building models within the framework of quantum field theory to explore what nature's structure might be and how to determine that structure through experiment.

    Suggested Preparation:

    High comfort with new mathematical techniques and concepts.

    Suitable for
    • Undergraduate students
    • Graduate students
  • Quantum Field Theory of Magnetic Charges

    Understand how magnetic charges (monopoles) arise and behave in quantum field theory with an eye toward new experimental search strategies.

    Suggested Preparation:

    Willing to learn quantum field theory and apply it to new and perhaps difficult situations.

    Suitable for
    • Undergraduate students
    • Graduate students
  • Understanding Nontopological Solitons

    Nontopological solitons are interesting objects that are possible macroscopic dark matter candidates. Making precise predictions of experimental signals depends on improving our theoretical understanding of these objects.

    Suggested Preparation:
    1. Willingness to learn classical field theory.
    2. Willingness to develop skills in mathematical methods and numerical methods
    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students
  • Dark Matter model building

    Developing models for the cosmological dark matter and determining their experimental signatures.

    Suggested Preparation:
    1. Willingness to learn fundamentals of cosmology 
      1. Includes analytical and numerical simulation of the early universe
    2. Willingness to learn classical field theory
    3. Willingness to learn quantum field theory concepts sufficient to apply them in model building.
    4. Willingness to learn open source computer codes to simulate cosmological dynamics and experimental signals.
    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students
  • Developing new models of Baryogenesis

    Building models of how the Universe came to have more matter than antimatter.

    Suggested Preparation:
    1. Willingness to learn fundamentals of cosmology 
      1. Includes analytical and numerical simulation of the early universe
    2. Willingness to learn classical field theory
    3. Willingness to learn quantum field theory concepts sufficient to apply them in model building.
    4. Willingness to learn open source computer codes to simulate cosmological dynamics and experimental signals.
    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students
  • Cosmological Phase Transitions and Defects

    Understand the creation and evolution of domain wall, cosmic strings, monopoles, and skyrmions in the early universe.

    Suggested Preparation:

    Willingness to learn classical field theory and likely numerical skills to simulate cosmic evolution of these object.

    Suitable for
    • Undergraduate students
    • Graduate students
    • REU students