Dr. Thomas Wilson
Posted on December 20, 2018
Marshall University Physics Professor Dr. Thomas E. Wilson’s research on high-frequency acoustics has resulted in the discovery of the acoustic equivalent of a laser, and will be reported as a Rapid Communication in Physical Review B, a leading scientific publication.
Abstract: We report first evidence for a 1.0 terahertz (THz) self-starting mirrorless acoustic phonon para- metric oscillator (MAPPO) produced from acousto-optic phase-conjugate degenerate four-wave (D4WM) mixing in a THz laser-pumped silicon doping superlattice (DSL). The DSL was grown by molecular beam epitaxy on a (100) boron-doped silicon substrate. A superconducting NbTiN subwavelength grating was used to couple the THz laser radiation into the DSL. Superconducting granular aluminum bolometric detection, coupled with Si:B piezophonon spectroscopy, revealed excitation of THz coherent compressional and shear waves, along the direction only. The Bragg scattering condition for distributed feedback, and the energy conservation requirement for the D4WM process, were both verified. A THz MAPPO could provide a testbed for studies of non-classical acoustic phonon fields.
The full publication is available at:
arXiv Scholarly Article Archive
American Physical Society
Dr. Maria Babiuc-Hamilton
Posted on December 18, 2018
Dr. Maria Babiuc-Hamilton, Associate Professor of Physics, and Dillon Buskirk, Graduate Student of Physics, have published “A complete analytic gravitational wave model for undergraduates” in the European Journal of Physics on December 12, 2018. It can be viewed online at IOP Science.
Abstract: Gravitational waves are produced by orbiting massive binary objects, such as black holes and neutron stars, and propagate as ripples in the very fabric of spacetime. As the waves carry off orbital energy, the two bodies spiral into each other and eventually merge. They are described by Einstein’s equations of General Relativity. For the early phase of the orbit, called the inspiral, Einstein equations can be linearized and solved through analytical approximations, while for the late phase, near the merger, we need to solve the fully nonlinear Einstein’s equations on supercomputers. In order to recover the gravitational wave for the entire evolution of the binary, a match is required between the inspiral and the merger waveforms. Our objectives are to establish an educational oriented toy model for a streamlined matching method, that will allow an analytical calculation of the complete gravitational waveform, while developing a gravitational wave modeling tutorial for undergraduate physics students. We use post-Newtonian (PN) theory for the inspiral phase, which offers an excellent training ground for students, and rely on \texttt{Mathematica} for our calculations, a tool easily accessible to undergraduates. For the merger phase we bypass Einstein’s equations by using a simple analytic toy model named the Implicit Rotating Source (IRS). After building the inspiral and merger waveforms, we construct our matching method and validate it by comparing our results with the waveforms for the first detection, GW150914, available as open-source. Several future projects can be developed based from this project: building complete waveforms for all the detected signals, extending the post-Newtonian model to take into account non-zero eccentricity, employing and testing a more realistic analytic model for the merger, building a separate model for the ringdown, and optimizing the matching technique.
Dr. Sean P. McBride
Posted on November 21, 2018
Dr. Sean P. McBride, assistant professor of physics at Marshall (Selected Works of Dr. Sean P. McBride), has been part of a collaboration of investigators studying the ability of self-assembled nanoparticle membranes to conform them to surfaces with Gaussian curvature. The collaboration’s research findings are presented in a recent publication in Soft Matter titled “Conforming nanoparticle sheets to surfaces with Gaussian curvature.”
Abstract: Nanoparticle monolayer sheets are ultrathin inorganic–organic hybrid materials that combine highly controllable optical and electrical properties with mechanical flexibility and remarkable strength. Like other thin sheets, their low bending rigidity allows them to easily roll into or conform to cylindrical geometries. Nanoparticle monolayers not only can bend, but also cope with strain through local particle rearrangement and plastic deformation. This means that, unlike thin sheets such as paper or graphene, nanoparticle sheets can much more easily conform to surfaces with complex topography characterized by non-zero Gaussian curvature, like spherical caps or saddles. Here, we investigate the limits of nanoparticle monolayers’ ability to conform to substrates with Gaussian curvature by stamping nanoparticle sheets onto lattices of larger polystyrene spheres. Tuning the local Gaussian curvature by increasing the size of the substrate spheres, we find that the stamped sheet morphology evolves through three characteristic stages: from full substrate coverage, where the sheet extends over the interstices in the lattice, to coverage in the form of caps that conform tightly to the top portion of each sphere and fracture at larger polar angles, to caps that exhibit radial folds. Through analysis of the nanoparticle positions, obtained from scanning electron micrographs, we extract the local strain tensor and track the onset of strain-induced dislocations in the particle arrangement. By considering the interplay of energies for elastic and plastic deformations and adhesion, we construct arguments that capture the observed changes in sheet morphology as Gaussian curvature is tuned over two orders of magnitude.
The full publication is available at Publishing by the Royal Society of Chemistry
DOI: 10.1039/C8SM01640B
Dr. Sean P. McBride
Posted on October 12, 2018
Dr. Sean P. McBride (Selected Works of Dr. Sean P. McBride) from Physics has contributed to efforts leading to the “Acquisition of a Field Emission Scanning Electron Microscope for Research and Teaching in the Fields of Chemistry, Geology, Biology, Physics, and Forensic Science.” This nearly $400,000 award has been provided by the National Science Foundation. This award is supported by the Major Research Instrumentation (MRI) and the Chemistry Research Instrumentation (CRIF) Programs as well as the Established Program to Stimulate Competitive Research (EPSCoR). Overall, the McBride Lab aims to study the behavior of liquids interacting with nanoparticles (NPs) in a variety of ways. When working on particles that are on the scale of several nanometers, having NP size characterizations techniques such as Field Emission Scanning Electron Microscopy have proven vital to the success of nearly any project.
National Science Foundation award information
Marshall University Parthenon article
Dr. Thomas Wilson
Posted on September 21, 2018
As part of the Third Thursday Presentation series, the Center for Teaching and Learning hosted a presentation by Dr. Thomas Wilson, Professor in the Physics Department and winner of the 2017-18 Marshall University Distinguished Artists & Scholars Award (Senior Recipient in Sciences and Technology). The title of his presentation was: “Advancements in Solid State Physics: Developing a Hyper-Ultrasound Laser”.
Dr. Maria Babiuc-Hamilton
Posted on September 5, 2018
Associate Professor in the Department of Physics at Marshall University, Dr. Maria Babiuc-Hamilton is currently part of the National Science Foundation (NSF) RII-EPSCOR gravitational waves project, administered by West Virginia Science & Research. Her research involves the development of methods for solving Einstein equations numerically in a full 3D code to simulate black hole evolution and to compute the gravitational waveform emitted by a binary system.
Click on the following links to see the video on your preferred platform: Website, Youtube, Facebook
Dr. Thomas Wilson
Posted on September 4, 2018
Dr. Thomas Wilson, professor of physics, presented a contributed paper at Phonons 2018 – The16th International Conference on Phonon Scattering In Condensed Matter, held May 30-June 3, 2018 in Nanjing, China. The title of his presentation was: “Terahertz Acoustic Phonon Lasing through Acousto-Optic Self-Oscillating Degenerate Four-Wave Mixing”. Wilson’s application to organize and host Phonons 2021 at Marshall University was accepted by the International Phonon Advisory Committee. Phonons 2021, to be held on the Huntington campus in June, 2021, will include the following topics: (1) phonon/heat transport, (2) electron-phonon interaction, (3) phonon-photon interaction, (4) quantum heat engine, (5) optomechanics, (6) phononic/thermal meta materials, (7) nonlinear phonons, (8) topological/chiral phonons, (9) phonon applications in quantum technologies, and (10) new phonon techniques, materials and phenomena.
Dr. Thomas Wilson
Posted on July 5, 2018
Dr. Thomas Wilson recently provided a talk at the 16th International Conference on Phonon Scattering In Condensed Matter and the 4th International Conference on Phononics and Thermal Energy Science at Nanjing, China. The title of his talk was Evidence for Terahertz Acoustic Phonon Lasing by Degenerate Acousto—Optical Four-Wave Mixing in Silicon Doping Superlattice.
Abstract: The archetype of a parametric oscillator is the playground swing. It can be driven from rest by a child’s leg kicks and chain pulls to a large amplitude, when the internal parameters occur at “twice” the natural frequency of the swing. For large angular amplitudes, the potential energy no longer precisely quadratic in amplitude, a prerequisite for parametric behavior. In my research, I drive, in a similar nonlinear manner using my custom nanosecond-pulsed terahertz laser, a nanoscale periodic crystalline doped structure (n-i-p-i doping superlattice) thereby creating a parametric terahertz acoustic wave oscillator. In a quantum picture, two photons are annihilated and two phonons are produced in this “four-wave mixing” scheme. The driven superlattice acts as a “distributed feedback” DFB laser so that self-oscillation occurs with a record gain for terahertz acoustic lasers. My system will provide a testbed for studying the non classical properties of phonons, in analogy to important current optical quantum optics.
Dr. Thomas Wilson
Posted on April 21, 2018
Dr. Thomas Wilson, professor of physics, at Marshall University has been named one of the recipients of the Marshall UniversityArtists and Scholars Award in Science and Technology. His award will be presented to him Monday April 23rd 2018 at the general Faculty Meeting in the Don Morris Room in the Memorial Student Center at 2pm. Wilson also recently presented an invited talk on March 20 to the Institute of Semiconductor Engineering at the University of Stuttgart, Germany, titled: “First Evidence for Terahertz Acoustic Phonon Laser via Four-Wave Mixing.” The superlattices for Wilson’s research were provided by his collaborators there. Wilson also met on March 22 for discussions on this topic with Dr. Bernard Perrin, Director of Research for CNRS, The Institute for Nanosciences of Paris, University of Pierre and Marie Curie, Paris, France.
Dr. Howard Richards
Dr. Howard Richards of the Department of Physics has developed a model for the NCAA men’s basketball tournament using nontraditional methods of physics. Richards, an assistant professor of physics, said the model is extremely simple and can be implemented using a Microsoft Excel spreadsheet.“It is not based on any team’s record this year, but only on the seed each team is assigned by the selection committee, which is assumed to capture – as well as it can be captured – the quality of a team. Wins and losses are the result of chance with the probabilities determined from two statistics: the record of upsets in first-round matches over the past 30 years, and the percentage of tournaments that have ended with a 1-seed as the final champion,” Richards said.
Designed as a way to show students that ideas of physics can be applied to nontraditional models, Richards said this project started as an introduction to physics research for a high school student and has since been used by a Canadian middle school teacher.
To learn more about Richards’ NCAA Tournament model, e-mail richardsh@marshall.edu or call 304-696-6466. For more information on programs in the Marshall University Department of Mathematics & Physics, visit department home page.
Dr. Thomas Wilson
Posted on March 7, 2018
Dr. Thomas Wilson, from the Department of Physics in the College of Science was one of Sixteen Marshall University faculty members selected for the John Marshall Summer Creative Works and Scholarship Award; each to receive the award is given a $6,500 stipend to help fund their projects during summer 2018. Wilson’s work is entitled, “Simulated Emission of Coherent Acoustic Phonons via Parametric Down-Conversion in Modulation-doped Superlattices Driven by Far-infrared Laser Radiation”. Awards give faculty members the opportunity to produce significant creative or scholarly output.
Projects funded through the awards program can involve research, design, development, field study, creative work or performance. The program is structured so participating faculty can produce creative or scholarly output—including presentations, publications, exhibits or performances—at the end of the award period.
Dr. Maria Babiuc-Hamilton
Posted on October 5, 2017 :
Dr. Maria Babiuc Hamilton and her collaborators recently published a paper in the journal Classical and Quantum Gravity, titled, “GiRaFFE: an open-source general relativistic force-free electrodynamics code.”
The paper comes with an open source code, “GiRaFFE,” which is able to simulate both gravitational and light waves emitted by sources like binary black holes and neutron stars. This is important, in the light of the recent detection of gravitational waves by three observatories, which makes it possible to determine the sky location of gravitational waves. This will allow prompt follow-up with telescopes, at last opening the skies to “multimessenger astronomy.” This new approach will tell astronomers much more about the physics of black hole collisions, gamma-ray bursts, and other powerful phenomena in space.
The research was supported in part by the National Science Foundation’s EPSCoR Research Infrastructure grant for Marshall and WVU: “Waves of the Future: Capacity Building for the Rising Tide of STEM in West Virginia” and the “Center for Gravitational Waves and Cosmology.”
This publication comes at the end of a busy summer for Dr. Maria Babiuc Hamilton. She was accepted into a Summer Program at the renowned Aspen Center for Physics where she participated in two workshops, was a Keynote speaker at the Green Bank Star Quest XV, presented at the National Youth Science Camp , and gave a talk on gravitational waves at the Blackwater Falls Astronomy Weekend, organized by the Kanawha Valley Astronomical Society. If interested in learning more about these events, please contact Dr. Maria Babiuc Hamilton about these events or visit her homepage.
Collaborators for the recent publication: (Zachariah B. Etienne and Sean T. McWilliams from West Virginia University, Mew-Bing Wan from the Zhejiang University of Technology, Hangzhou, China, and graduate student Ashok Choudhary.)
Journal: Classical and Quantum Gravity (Classical and Quantum Gravity, vol. 34, no. 21, 27 September 2017.)
Observatories: (including the new Virgo)
Dr. Jon Saken
Posted on August 15, 2017 :
A team of students led by Dr. Jon Saken from Marshall University representing the West Virginia Space Grant Consortium will launch a high-altitude balloon on Monday, Aug. 21, as part of a nationwide, NASA-sponsored project to live-stream aerial video footage of the “Great American Eclipse.”
The team will launch the roughly 8-foot-tall, helium-filled balloon, which will carry a video camera and other equipment to an altitude of up to 100,000 feet, at approximately 12:20 p.m. CDT (1:20 p.m. EDT) from a remote site in southern Illinois.
WCHS ABC 8 Eyewitness News Reports
Time lapse footage (feel free to mute or lower the volume on your speakers first).
Dr. Thomas Wilson
Posted on July 25, 2017
Thomas Wilson, Professor of Physics, Marshall University (http://science.marshall.edu/wilsont/ ) has won the Low-Cost Apparatus Competition with his Kelvin Current Balance at the American Association of Physics Teachers (AAPT) Summer Meeting 2017 in Cincinnati, Ohio (July 22-26, 2017). See picture to the right showcasing the award winning apparatus. View the full description
Dr. Sean P. McBride
Posted on July 24, 2017
Dr. Sean P. McBride, Tenure Track Assistant Professor of Physics at Marshall University, has been part of a collaboration of investigators studying the mechanical response of self-assembled nanoparticle membranes when they are exposed to changes in temperature and other environmental stimuli. The collaboration’s research findings are presented in a recent publication in ACS Nano entitled “Thermomechanical Response of Self-Assembled Nanoparticle Membranes”. The publication can be viewed online:here or here.
In addition to McBride, members of this collaboration included Dr. Yifan Wang, lead author currently at California Institute of Technology, who worked with research mentor and co-author Dr. Heinrich M. Jaeger at the James Franck Institute and the Department of Physics at University of Chicago, and fellow co-authors Drs. Henry Chan, Badri Narayanan, and Subramanian K. R. S. Sankaranarayanan, and Xiao-Min Lin, who are all researchers from the Center for Nanoscale Materials at Argonne National laboratory.
Recently, self-assembled nanoparticle monolayer membranes consisting of nanometer sized metallic or semiconducting particle cores capped with short organic ligands have attracted considerable attention. This is because these membranes can easily be formed via self-assembly techniques at liquid vapor interfaces and maintain the unique optical, electronic, or magnetic functionality of the core nanoparticles. These types of ultra-thin membranes have demonstrated potential uses such as drumhead resonators for potential use in sensors and filtration membranes for potential use in water purification applications. Understanding the mechanical response from these types of membranes under different external stimuli found in Nature, such as temperature and humidity, is of great importance for use in such applications.
Abstract: Monolayers composed of colloidal nanoparticles, with a thickness of less than 10 nm, have remarkable mechanical moduli and can suspend over micrometer-sized holes to form free-standing membranes. In this paper, we discuss experiments and coarse-grained molecular dynamics simulations characterizing the thermomechanical properties of these self-assembled nanoparticle membranes. These membranes remain strong and resilient up to temperatures much higher than previous simulation predictions and exhibit an unexpected hysteretic behavior during the first heating−cooling cycle. We show this hysteretic behavior can be explained by an asymmetric ligand configuration from the self-assembly process and can be controlled by changing the ligand coverage or cross-linking the ligand molecules. Finally, we show the screening effect of water molecules on the ligand interactions can largely change the moduli and thermomechanical behavior.
Dr. Sean P. McBride
Posted on May 6, 2017
Dr. Sean P. McBride, Assistant Professor in the Physics Department, was invited to be the inaugural guest Blogger on the new Center for Teaching and Learning Blog. On this post, Dr. McBride describes how the use of Blackboard analytics helps both teachers and students. The overall aim of the blog is to provide fellow faculty with a resource revolving around teaching innovation and teaching experiences from faculty. In the inaugural post, Dr. McBride gives the descriptions of the classes that he has incorporated Blackboard into and how he uses Blackboard to achieve the objectives of those classes. At the end of the blog, Dr. McBride offers the reader statistical data in the form of plots generated by Blackboard. These plots address some of the below basic questions faculty may have about their courses:
- How often does the current generation of tech savvy students really use Blackboard?
- I use Blackboard, but I wonder which students are actually looking at the material I have posted?
- What day of the week and hour of the day do students access Blackboard?
- How long does each student spend in Blackboard and what are they looking at?
- Will my students check Blackboard more often than if I just post class material on the cork board outside my office?
- Is there any data that suggests students who access the material posted in Blackboard perform better than those students who chose not to access the provided materials in Blackboard?
The data used for the plots was extracted from one of Dr. McBride’s own classes this spring 2017 semester. Dr. McBride will continually update these stats for this particular class on his own teaching web page.
In summary, as of 5/6/2017 his course has had 13,802 page hits from the 26 students who completed the class and the entire class from day 1 has logged nearly 1,037 hours outside of class on Blackboard; so yes, the current generation of tech savvy students really do use Blackboard. The data also seems to suggest that the specific students who use Blackboard do better in class.
To set-up your own courses in Blackboard, see the experts in the Design Center in Room 235, Drinko Library, Monday – Friday, 8:00 am – 4:30 pm, 304-696-7117, designcenter@marshall.edu.
Dr. Sean P. McBride
Posted on March 8, 2017
Bruce M. Law, Professor of Physics, Kansas State University, Sean P. McBride, Assistant Professor of Physics, Marshall University, and a host of international collaborators from leading institutions from around the worldi have published “Line tension and its influence on droplets and particles at interfaces” as a review article in Progress in Surface Science, volume 92, pages 1-39, 2017. It can be viewed online.
The line tension parameter, τ is a result of excess energy caused by the imbalance of the complex intermolecular forces experienced at the three-phase contact line and plays a key role in the stability of particles at interfaces. This review addresses the differences in the sign and magnitude of τ over the different length scales over which it acts.
Abstract: In this review, we examine the influence of the line tension τ on droplets and particles at surfaces. The line tension influences the nucleation behavior and contact angle of liquid droplets at both liquid and solid surfaces and alters the attachment energetics of solid particles to liquid surfaces. Many factors, occurring over a wide range of length scales, contribute to the line tension. On atomic scales, atomic rearrangements and reorientations of sub-molecular components give rise to an atomic line tension contribution τatom (∼1 nN), which depends on the similarity/dissimilarity of the droplet/particle surface composition compared with the surface upon which it resides. At nanometer length scales, an integration over the van der Waals interfacial potential gives rise to a mesoscale contribution |τvdW| ∼ 1–100 pN while, at millimeter length scales, the gravitational potential provides a gravitational contribution τgrav ∼ +1–10 μN. τgrav is always positive, whereas, τvdW can have either sign. Near wetting, for very small contact angle droplets, a negative line tension may give rise to a contact line instability. We examine these and other issues in this review.
iSee link for full Author list
Dr. Thomas Wilson
Posted on February 22, 2017
Zhi Liang, Professor of Mechanical Engineering, California State University – Fresno, Thomas Wilson, Professor of Physics, Marshall University, and Pawel Keblinski, Professor and Department Head, Materials Science and Engineering Department, Rensselaer Polytechnic Institute, have published “Phonon interference in crystalline and amorphous confined nanoscopic films” in the Journal of Applied Physics, Volume 121, Issue 8, 075303, February 28, 2017. It can be viewed online.
Phonons are the primary thermal energy carriers in semiconductor devices. As the size of semiconductor components in microelectronics reduces to nanoscale, phonon scattering at material interfaces can strongly affect thermal transport in nanostructured components. It has been found in numerous experiments and numerical simulations that the specular reflection and transmission of phonon waves at interfaces of nanostructured components may result in phonon interference effects which can be used for the modification of phonon dispersion and for controlling nanoscale heat transport.
Abstract: Using molecular dynamics phonon wave packet simulations, we study phonon transmission across hexagonal (h)-BN and amorphous silica (a-SiO2) nanoscopic thin films sandwiched by two crystalline leads. Due to the phonon interference effect, the frequency-dependent phonon transmission coefficient in the case of the crystalline film (Si|h-BN|Al heterostructure) exhibits a strongly oscillatory behavior. In the case of the amorphous film (Si|a-SiO2|Al and Si|a-SiO2|Si heterostructures), in spite of structural disorder, the phonon transmission coefficient also exhibits oscillatory behavior at low frequencies (up to ∼1.2 THz), with a period of oscillation consistent with the prediction from the two-beam interference equation. Above 1.2 THz, however, the phonon interference effect is greatly weakened by the diffuse scattering of higher-frequency phonons within an a-SiO2 thin film and at the two interfaces confining the a-SiO2 thin film.
If you have any news such as publications, awards, departmental news, or anything else you want to share,
please email Dr. Sean McBride (mcbrides@marshall.edu).
Contact mcbrides@marshall.edu if you have trouble accessing the Physics Department website or experience errors. Questions about the content can also be addressed to mcbrides@marshall.edu.