Physics Colloquium

A new year, a new chance to get involved in the Physics Department. Join us as we gather for the first Friday of the new school year to meet and share what's going on in physics!

Catch up with old friends and meet new ones as we say hello to all our fellow physics faculty and students. We will also share information about what is happening in the department. Join us to learn about student work opportunities, research opportunities, joining the Society of Physics Students and our colloquia series.

Pizza and drinks will be available in Hayes Hall 215 on Friday, August 30, from 11:45 a.m. to 12:15 p.m. Grab a slice and head to Hayes 211/213 for the presentation. We hope to see you there!

Two-dimensional transition metal dichalcogenide (2D-TMD) systems are a rich field of research within condensed matter physics. The large variety of physical characteristics exhibited by this class of material have led to wide interests, mainly due to its potential applications in optics and information systems. In this presentation I propose to conduct spectroscopic ellipsometry studies on several 2D-TMD systems, determining their thickness-dependent dielectric functions. Concurrently, I propose to conduct computational studies on these 2D-TMD systems using Density Functional Theory (DFT). DFT is a computational approach to determine the band structure and the dielectric functions of condensed matter systems. Implementing the DFT tool in our lab will enable us to perform theoretical/computational studies on materials we investigate, enabling us to corroborate the experimental results with first principles calculations. 

Join us on Friday, Sept. 6, for the first of this year's honors talks presented by physics students pursuing honors. Lunch will be available in Hayes 216 from 11:45 a.m. to 12:15 p.m. and the presentation will begin in Hayes 211/213 at 12:10 p.m. Come and support your fellow physics classmates. We hope to see you there!

"Thirty years ago, I was a physics graduate student. I left without finishing my doctorate and switched careers. Instead of trying to do science, I now write about science at the New York Times. Science and equations are precise. Words are not. Writing about science is a series of tradeoffs, explaining the big picture for non-scientific readers while fuzzing the details. How well do I do? How well would you do?"

We're excited to invite you to join us on Friday, Sept. 13, to gain insights on writing, science and communicating scientific concepts from Kenneth Chang, science reporter at the New York Times. Enjoy a complimentary lunch in Hayes 216 from 11:45 a.m. to 12:15 p.m., followed by an engaging presentation in Hayes 211/213 at 12:10 p.m. Don't miss out on this opportunity! See you there!

Nobel Laureate in chemistry and professor of biochemistry and molecular biophysics and biological sciences at Columbia University Irving Medical Center, Joachim Frank will visit Kenyon for several presentations on Sept. 17. The first of these presentations will be on time-resolved cryo-EM and its impact on structural biology.

The standard protocol of cryo-EM does not allow visualization of reactions since the time for sample deposition on the grid and blotting is in the range of several seconds. To study the process of a reaction, as it goes through one or more short-lived intermediates, we have developed a method of time-resolved cryo-EM. Here two reactants are mixed in a microfluidic channel, allowed to react for a defined time (between 10 and 1000 milliseconds), and the reaction product sprayed onto the EM grid as the latter is being plunged into the cryogen. Novel PDMS-based microfluidic chips prove to give exceptional reproducible results.  

With this approach we have been able to visualize short-lived states of the ribosome in different stages of its work cycle making proteins. Applications in the study of many other molecular machines are possible.

The Natural Sciences Division invites you to join us in the Higley Auditorium from 11:10 a.m. - noon for this amazing opportunity and discussion. We hope to see you there for this exciting presentation!

Nobel Laureate in chemistry and professor of biochemistry and molecular biophysics and biological sciences at Columbia University Irving Medical Center, Joachim Frank will visit Kenyon for several presentations on Sept. 17. The second of these presentations will be on the processes and impact of cryogenic electron microscopy.

Cryogenic electron microscopy (cryo-EM) has transformed the way we can study biological molecules as it enables us to determine structure of molecules freely suspended in solution (as “single particles”), and to gauge the way they change their shape as they interact with one another in the cell. Freezing, by plunging the sample rapidly into a cryogen at liquid nitrogen temperature, is necessary to trap the molecules in a fixed position in vitreous ice for imaging and to reduce the damage inflicted by the electrons in the process.

Following the introduction of novel cameras for detecting single electrons, near-atomic resolution has been achieved for many molecules and molecular machines of biomedical relevance, including ion channels and receptors. Most recently cryo-EM has contributed in major ways to the development of vaccines and cures for COVID-19.

The Natural Sciences Division invites you to join us in the Oden Auditorium from 7 - 8 p.m. for the second of these two presentations from Nobel Laureate Joachim Frank. This presentation is open to all members of the Kenyon community. We hope to see you there for this exciting presentation!

The soil dwelling bacterium Myxococcus xanthus is an amazing organism that uses collective motility to hunt in giant packs when near prey and to form beautiful and protective macroscopic structures comprising millions of cells when food is scarce. I will present an overview of how these cells move and how they regulate that motion to produce different phases of collective behavior. Inspired by recent work on active matter and the physics liquid crystals, I will discuss experiments that reveal how these cells generate nematic order, how defect structure can dictate global behavior, how transient polar states govern the ultimate dynamics, and how cells actively tune the Péclet number of the population to drive a phase transition from a gas-like flocking state to an aggregated liquid-droplet state during starvation.

The Natural Sciences Division invites you to join us in Hayes Hall 109 on Thursday, Sept. 19, at 11:10 a.m. for this presentation from Joshua Shaevitz, professor of physics and biophysics at Princeton University. Lunch will be available after the talk for attendees who wish to stay and meet with Shaevitz. We also invite students to meet Shaevitz on Wednesday, Sept. 18, at 4 p.m. in Mather 306 for an info session on science careers and graduate school careers. We hope to see you there!

The magneto-optical Kerr effect (MOKE) occurs when linearly polarized incident light changes its polarization state of the reflected light due to its interaction with a magnetic sample. In general, the reflected light off of a sample, when subjected to a magnetic field, will alter its polarization from linear to elliptically-polarized light. This polarization change can be described and measured via the Kerr rotation and Kerr ellipticity parameters, which together provide insights on the magnetic behavior of the sample. Such measurements will be necessary to advance our knowledge on magnetic materials that are potential candidates to advance quantum computing and optoelectronic devices. I am proposing to build a spectroscopic MOKE experiment to investigate the Kerr effect of interesting magnetic materials. This will involve assembling several optical components, performing optical alignment, integrating electronics and writing the necessary LabVIEW codes to fully automate the MOKE system. Finally, the spectra of magnetic materials obtained by MOKE and ellipsometry will be analyzed to recover the dielectric tensor, which is needed to fully characterize the optical, electrical and magnetic properties of the material.

Join us on Friday, Sept. 27, for the last of this year's honors talks presented by physics students pursuing honors. Lunch will be available in Hayes 216 from 11:45 a.m. to 12:15 p.m. and the presentation will begin in Hayes 211/213 at 12:10 p.m. Come and support your fellow physics classmates. We hope to see you there!