Theoretical & Computational Physics

Martin Bier is interested in thermodynamics, dynamical systems, complex networks, and stochastic processes. Through a combination of computer simulations, data acquisition, and theoretical approximations, his research group tries to understand how and why systems behave the way they do. This method can be used to analyze the propagation of infectious disease, the transduction of energy through biomolecules, the transfer of stocks, etc.

Learn more about Dr. Bier’s research

Maxwell’s demon is a thought experiment first proposed 150 years ago. Later variations on Maxwell’s idea, shown above, are called Maxwell zombies.

Michael Dingfelder seeks to understand how ionizing radiation affects biological matter. This includes the calculation of interaction cross sections and the development of transport models. These cross sections and models are implemented into Monte Carlo track-structure simulation codes that are used to simulate and predict radiation damage to biological targets, such as DNA or cell constituents. This is part of an ongoing investigation into radiotherapy, where DNA single- and double-strand breaks in large numbers are considered essential for cell termination. This is important because misrepaired DNA damage can lead to mutations and possibly the onset of cancer.
Gregory Lapicki compiles and calculates X-ray production cross sections (XRPCS) for protons and other ions that produce X-rays in atomic inner shells. These XRPCS are required for reliable analyses of elemental composition and concentration of materials as is done with the particle-induced X-ray emission (PIXE) technique. He has developed the ECUSAR theory which is in excellent agreement with L-shell XRPCS for protons. In further studies, he plans to extend this work to K- and M-shell ionizations by protons and heavier ions.

(top) Compiled data for 5,771 total L-shell XRPCS for proton energies 26 eV ≤ E ≤ 1 GeV and all elements with 24 ≤ Z ≤ 95; universal fit is shown in green. (bottom) Dr. Gregory Lapicki speaking at a conference.

The collision of two gold nuclei at high energy as calculated from A Multi-Phase Transport (AMPT) model. The length of the box is 60 fm (6×10−14 m), while time covers the first 30 fm/c (1×10−22 s) of the collision.

Zi-Wei Lin performs research in theoretical and computational physics. His interests include

  • high-energy heavy ion physics and the development of Monte Carlo transport models,
  • radiation physics and space radiation protection, and
  • medical physics in pseudo-CT methods for MRI-only radiotherapy.

These projects involve undergraduate and graduate students, postdoctoral researchers, as well as visiting students and professors.

Learn more about Dr. Lin’s research