Research Areas
Catholic University REU Research Areas
Nuclear Physics
Project: Emergent Mass in QCD
Atomic nuclei lie at the core of everything we can see; and at the first level of approximation, their atomic weights are simply the sum of the masses of all protons and neutrons they contain. Each nucleon has a mass of ~1 GeV, i.e. approximately 2000 times the electron mass. The Higgs boson produces the latter, but what produces the masses of the proton and neutron? We will investigate experimentally, using data from the 12 GeV Jefferson Lab, the mechanism that dynamically generates nearly all of the mass of these light hadrons, and so our visible universe.
Project: Hunting Exotic Hadrons: a Frontier of QCD
The goal of the GlueX experiment at Jefferson Lab is to search for and study hybrid and exotic hybrid mesons. This provides a way for testing QCD, the theory of strong interactions, in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom.
The search for new mesons requires very specialized instrumentation and analysis methods since such states are rare and must be established through their decay to lighter and longer-lived particles. We will use real data from GlueX to search for hybrid mesons and also devise optimizations for the detection of these mesons.
Computational Physics
Project: Machine Learning and Detector Optimization
Advanced detector R&D requires performing computationally intensive and detailed simulations as part of the detector-design optimization process. We will use a general approach to this process based on Bayesian optimization and machine learning that encodes detector requirements. As a case study, we will focus on the design of particle identification detectors at the Electron-Ion Collider, a US-led frontier facility to further explore the structure and interactions of matter at the scale of sea quarks and gluons.
Physics Instrumentation and Technology
Project: Detector Technology and Instrumentation
The development of cutting-edge particle detection instrumentation demanded by increasingly sophisticated experiments plays a critical role in the success of nuclear physics research. Such detectors also have application in areas as diverse as medical imaging, detection of special nuclear materials, and port security. These detectors are based on novel materials such as aerogels, single crystals, and glasses. Advanced detectors require optimization of these materials and the associated instrumentation. In this project, REU students will design and build prototypes, use advanced instrumentation, carry out small-scale experiments, and analyze and interpret data to optimize detector parameters such as luminescence and radiation hardness. Students will obtain hands-on experience in particle detection techniques, electronics, data analysis and interpretation, and synergies between particle detector construction and material properties.
Nanotechnology and Device Physics
Project: Electron Spin Transport Studies In Metals
The fundamentals of future spin-based electronic circuit design are the generation and transport of spin-polarized electrons. The promise of non-volatile, low-power spintronics depends on the fabrication and characterization of suitable materials and devices, including those with a long spin lifetime and spin diffusion length. Emerging research shows the appearance of these useful properties in nanoscale materials, which is not present in bulk materials. The REU student will fabricate nanoscale devices using thin films of metallic films and measure transport in metals and investigate the spin transport properties using a quantum-mechanical non-local measurement scheme. In particular, the challenges and methods of fabricating high-quality ferromagnetic tunneling contacts on metallic channels will be investigated. Spin transport in metals at the nanoscale is an area of active research. This study forms the foundation to understand the effect of spin-orbit interaction strength and dimensionality on spin relaxation and hence, the spin lifetime of the electrons in these channels. The students will be trained on scanning electron microscopy-based electron-beam lithography and on transport measurement techniques using a Quantum Design physical property measurement system. The students will be able to analyze the data and understand the spin transport through the metallic channels.
Single-Molecule Biophysics
Project: Single Molecule Measurements on Biopolymers and Computational Biological Physics
Our research projects use computational and experimental techniques drawn from physics to help elucidate important questions in biology. The experimental side of the research is built around a newly developed magnetic tweezers system with a number of advanced capabilities. This instrument enables highly precise micromechanical measurements on single DNA-protein complexes. REU students will spend four weeks learning the experimental protocols under the guidance of Dr. Sarkar and senior graduate students. Our past experience has shown that students can be trained in this time to carry out full-fledged experiments. The first group of experiments will consist of obtaining calibration data and determining the degree of reproducibility of the data. This will teach students the importance of the accuracy and precision of measurements and how these are quantified - this should take another four weeks. After learning the techniques, students will study the minimum critical force required to drive proteins off the DNA tether as a function of protein concentration, presence of competitor proteins, and in various salt conditions. These data are currently not available and would be important for understanding their roles inside cells. Students will learn important concepts in statistical physics and molecular biology and how to carry out data analysis. They will also be exposed to the rigors of careful experimentation and come to appreciate the many facets of the craft of experimental physics. On the computational side, we have an ongoing collaboration with the Epithelial Systems Biology Laboratory at the National Heart, Lung, and Blood Institute of the National Institutes of Health involving development of novel computational tools to search and interrogate large biological databases. Many large-scale databases are being generated routinely; an ongoing research problem is to find computational approaches for sifting through the data and for drawing useful inferences from the data. Our collaboration has led to the development of publically available databases and web-accessible software for performing a variety of analytical tasks with such databases. There are many opportunities for students to participate in this exciting new area of research. Projects can involve development and testing of software, physics-based modeling of biological systems, and database development and validation.
