RESEARCH AND SCHOLARSHIP
Physics faculty are engaged in research ranging from the structure of matter to the expansion of the universe, with numerous opportunities for student involvement.
Broadly, most physics research at 棉花糖直播 can be divided into two major fields: Condensed Matter Physics and Astrophysics.
RESEARCH AREAS
CONDENSED MATTER PHYSICS
Condensed matter physics is the study of the properties of matter, including superconductivity, magnetism, thermal transport and spintronics. It is one of the largest fields in modern physics, with applications in chemistry, biology and nanotechnology.
, studies the physics of magnetism in matter. While magnetism, which arises from interactions between unpaired electrons, has been known since ancient times, many mysteries still remain. In particular, he is interested in materials in which magnetic ordering is more spatially complex than in simple cases of ferromagnetism (as occurs in metallic iron and related materials). His research focuses on geometric magnetic frustration, in which the arrangement of magnetic ions inhibits the development of magnetic order. Frustration gives rise to a rich variety of magnetic states and provides a window into exotic physics inaccessible in more conventional materials.
His research involves both work on campus, and experiments performed at national laboratories. He has set up a synthesis laboratory on campus, which includes an x-ray diffractometer to characterize crystalline structure, and frequently travel to large facilities including Oak Ridge National Laboratory and TRIUMF to perform definitive characterization using neutron and muon beam radiation. Over the past five years Dr. Carlo has had eight undergraduate research students, who have participated in sample synthesis as well as experiments at national laboratories, and they have presented their results at regional and national American Physical Society meetings. He is always happy to welcome new students into his group, where they will experience research using a diverse set of techniques, and the opportunity to perform research at national laboratories in collaboration with colleagues from the US and Canada.
Scott Dietrich, PhD, studies the nanoscale motions and interactions of charge in a family of crystals known as van der Waals materials. Many people consider electricity as flowing like water in a pipe, but this analogy breaks down when the electrons interact strongly. This collective behavior of electrons in a material is often greater than the sum of its parts 鈥� more is different. Exciting new electronic properties result when interactions dominate; electrons can crystallize, superconduct, coalesce, or more. Dr. Dietrich investigates the electronic properties of van der Waals materials when reduced to a sheet of single-atom thickness. Graphene, a single sheet of carbon atoms, is the flagship material of this family. van der Waals materials hold exciting potential for applications in next-generation technology and continue to be a unique playground to study physics in two dimensions. Dr. Dietrich鈥檚 research aims to bridge the gap between physics and engineering so these materials can be used in future electronic devices.
Dr. Dietrich directs the 2D Materials Laboratory within the Physics Department. This space allows researchers to generate single atomic layers and build larger structures by combining different materials. An atomic force microscope characterizes materials and measures electromechanical properties at the nanoscale. Student researchers learn to use the tools and often become users of the nanofabrication facilities at the University of Pennsylvania. Potential student projects range from computational simulations to hands-on construction and characterization of van der Waals structures.
Georgia Papaefthymiou-Davis, PhD, directs the M缨ssbauer Spectroscopy and High Energy Ball Milling Laboratories within the Department of Physics at 棉花糖直播 University. Her expertise lies in nanoscience and nanotechnology with special emphasis on nanoscale magnetism, fundamentals, and applications to devices, biotechnology and medicine. Her research focuses on compounds related to iron: ferrites, multiferroic materials and engineered human ferritins (compounds that store and release iron). She collaborates with chemists, biologists, materials scientists and engineers within 棉花糖直播 and at other national and international research centers and universities.
Dr. Papaefthymiou-Davis welcomes students to join her ongoing collaborative research efforts or to design their own research projects. In addition to M缨ssbauer spectroscopy, the students can acquire expertise in mechanochemical synthesis of nanoferrites, X-Ray powder diffraction, Transmission Electron Microscopy, Scanning Electron Microscopy, Atomic Force Microscopy and specific absorption rate measurements in heat transfer processes. All necessary instrumentation is available on Campus within the College of Sciences or the School of Engineering.
ASTROPHYSICS
Astrophysics is the study of physical processes as they occur in space, including gravity, atomic and chemical interactions, the formation of planets, stars, and galaxies, and the large-scale evolution of the universe.
, works on the development and use of new instruments to study the universe in polarized light at long wavelengths. He is currently involved in two such instruments. The first is the Cosmology Large Angular Scale Surveyor (CLASS), which is an array of telescopes located in the Atacama Desert in Chile. CLASS measures the polarization of the Cosmic Microwave Background (CMB), which is the afterglow of the Big Bang, in search of evidence that the universe underwent a rapid exponential expansion called inflation in the first fraction of a second. His lab has developed hardware to support the development of CLASS, and undergraduate students have played a key role in these efforts.
Dr. Chuss鈥檚 group at 棉花糖直播 also is part of a team that just delivered a new instrument for NASA鈥檚 Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is an airborne observatory that consists of a 1.5-meter telescope mounted inside a modified Boeing 747 aircraft. Because the observatory operates at altitudes around 45,000 feet, SOFIA is able to observe at far-infrared wavelengths of light that get mostly absorbed by the atmosphere. The new instrument, HAWC+ polarimeter, is used to study the role of magnetic fields in star formation in our Milky Way Galaxy. The instrument is currently obtaining new data that are an order of magnitude beyond the former state of the art.
Students have worked on projects with Dr. Chuss ranging from data analysis to development and production of hardware. Students have also conducted research in the field both on SOFIA flights and in the Atacama Desert
studies the physics of black hole accretion. Material falling towards a black hole (鈥渁ccreting鈥� onto the black hole) can release enormous amounts of energy, and a significant fraction of this material may in fact be ejected before it reaches the event horizon. He uses NASA鈥檚 X-ray telescopes in space (including Chandra, NICER, and NuSTAR) to study the behavior of gas as it falls towards the black hole and to look for signatures of any ejected material. Dr. Neilsen is very happy to have new students in his group, and he has lots of observations of black holes for them to work on. He and Amber Stuver, PhD, share a computer research lab鈥攖he 鈥淕ravity Lab鈥濃�攚here students have access to fast workstations and all the software they will need. Dr. Neilsen has research collaborations around the world, and can offer research projects on stellar-mass and supermassive black holes involving theory or data, spectroscopy, variability analysis, statistical analysis and occasionally even general relativity. Students working with Dr. Neilsen may get their results published in a physics or astronomy journal and may have the opportunity to present their work at regional or national conferences.
With great sadness, the Physics Department announces the death of their beloved colleague Amber Stuver on Sunday, September 8, 2024.
, uses LIGO (Laser Interferometer Gravitational-Wave Observatory) to observe gravitational waves from some of the most violent and energetic events in the universe like colliding black holes and merging neutron stars. In order to detect gravitational waves, physicists need to be able to make length measurements smaller than a thousandth the size of a proton which corresponds to a large amplitude gravitational wave when it arrives at Earth. Physicists are more than capable of doing this, but they are also constantly measuring the effects of environmental disturbances and instrumental glitches.
Dr. Stuver studies how these glitches affect the data and how to improve the quality of the data by either removing contaminated times or eliminating the source of the glitch. This involves a deep understanding of both the detector and the data analysis methods that extract gravitational wave signals from the noise.
Currently, she is working on improving data quality for the search for burst gravitational waves (short duration signals that come from sources that aren鈥檛 well modeled or are unanticipated). This utilizes existing tools developed by LIGO and machine learning methods, including the citizen science and machine learning project called Gravity Spy to safely remove them from the data or to discern their origin. Students in Dr. Stuver鈥檚 group earn authorship on LIGO Scientific Collaboration publications by learning how the LIGO detectors operate and how to computationally manipulate real data, and by using software, sometimes that they've develop, to study glitches that contaminate the data.
FACULTY EARN NSF REU GRANT
Amber Stuver, PhD, assistant professor of Physics, and Scott Engle, PhD, assistant professor of Astronomy and Planetary Science, received a Research Experience for Undergraduates (REU) Site Grant from the National Science Foundation. The REU site provides promising undergraduate students from other institutions, who wouldn't otherwise have much exposure to research, the opportunity to participate in discovery-based research, professional training, and community building activities.