Student-Faculty Research Flourishes in Physics Department
Undergraduate research is thriving in the Physics Department. Current students Learn by Doing research with faculty mentors on projects as massive as black holes and as tiny as nanometer-thick liquid crystal films. Read what they've been up to below.
Vardha Bennert's Team
Students Work to Classify Galaxies
Maren Cosens at the Lick Observatory.
In April 2015, physics major Sean Lewis and mechanical engineering major Maren Cosens joined Professor Vardha Bennert for an observing run at the three-meter Shane telescope at the Lick Observatory, located on Mt. Hamilton east of San Jose.
They observed emission-line clouds outside of galaxies discovered by Galaxy Zoo, an online astronomy project that invites members of the public to assist in the structural classification of large numbers of galaxies. The origin of these emission-line clouds is unknown, and the team used spectroscopy to shed light on their nature.
Alumni Co-Author Paper on Fading Active Galactic Nucleus Candidates
Together with their senior thesis advisor, Professor Vardha Bennert, physics alumni Bryan Scott, Charlie Showley and Kelsi Flatland co-authored a peer-reviewed paper on so-called fading active galactic nuclei observed with the Hubble Space Telescope (HST). The paper was published in the The Astrophysical Journal, the leading journal for astronomy and astrophysics in the U.S.
While still at Cal Poly, these alumni helped with observations at the Shane telescope that led to the sample selection of these galaxies. For all eight galaxies, HST observations reveal evidence of ongoing or past galaxy interactions and mergers including tidal tails, shells and warped or chaotic dust structures. The very extended ionized gas is composed of tidal debris rather than galactic winds. The host systems are bulge-dominated and show no strong evidence of triggered star formation in luminous clusters.
The article is titled "HST Imaging of Fading AGN Candidates: Host-Galaxy Properties and Origin of the Extended Gas."
Jonathan Fernsler's Team
Research Experience for Undergraduates Offered at University of Colorado
Vincent Nguyen gives his final presentation on liquid crystal
films at the University of Colorado, Boulder.
Physics students Vincent Nguyen and James Amarel spent the summer doing a Research Experience for Undergraduates (REU) funded by Professor Jonathan Fernsler’s National Science Foundation grant. They traveled to the University of Colorado at Boulder and worked at the Soft Materials Research Center running experiments on freely suspended liquid crystal films. These films are the thinnest fluid films known and can be regularly created with a thickness of only one molecule, i.e., one nanometer thick.
Nguyen studied 2D hydrodynamics of interacting islands, which are thicker regions of film, and Amarel studied active matter of oil drops propelled by surfactant that can model simple living systems. These results are now being analyzed back at Cal Poly, and Amarel is building an active matter experiment in Fernsler’s Baker Center lab.
New Liquid Crystal Behavior Discovered
Electrical engineering student Xem Muscarella and double-major in mechanical engineering and physics Taylor Best studied electro-optics of liquid crystals and discovered a new behavior. They sandwiched liquid crystal cells between glass with a transparent conducting layer that makes it possible to apply a voltage across the liquid crystal.
Applying a voltage to the cell switched the optic axis of the liquid crystal, as expected, but after removing the voltage, the optic axis remained in place for approximately a minute. This electrostatic response is analog, where the optic axis can be frozen wherever desired, and is a previously unrealized behavior in the scientific literature. Fernsler, Muscarella and Best are now examining how this behavior occurs and expect to publish a journal article in the coming year.
Students Build a Microscope out of Legos
The Lego Brewster Angle Microscope in the Physical
Chemistry Lab. It will be used to study synthetic lung
surfactant that could serve as improved surfactant
therapy for prematurely born babies.
Physics student Vincent Nguyen and chemistry student Nick Benz built a Brewster Angle Microscope (BAM), which can image a one-nanometer thick monolayer on the surface of water. The microscope uses a laser reflected off the surface at a precise angle.
An unusual twist on this BAM is that it is built almost entirely out of Legos. Using two computer-controlled motors from a Lego Mindstorm kit, the BAM adjusts the angle of reflection with one motor and adjusts the focus of the image with the other. Because the BAM views the monolayer at an oblique angle, only a section of the image is in focus, but Nguyen wrote software that combines the images taken at different focal points to create a composite image that is in focus. This feature is usually only seen in BAM’s costing approximately $100,000.
Physics student Jessica Pilgram and chemistry students Hunter Vanderpoel and Alison Wallum continued work on the BAM, which was used in Chemistry 354, the upper division physical chemistry lab, to image several monolayers and teach students about 2D thermodynamics.
During the 2015-16 academic year, the BAM will be used to study synthetic and native lung surfactant, a coating on the surface of the lungs necessary for breathing. Lung surfactant therapy is used primarily on prematurely born babies, who lack a functioning surfactant. The team will also submit a paper — including a Lego manual on how to build a BAM — to the American Journal of Physics.
Scott Fraser's Team
Maximally Charged Black Holes Minimize Total Energy
A simulated black hole of 10 solar masses as seen from a
distance of 600 kilometers with the Milky Way in the background.
Image compliments of Ute Kraus, Physics education group
Kraus, Universität Hildesheim, CC BY-SA 2.5
Working with Professor Scott Fraser, graduating senior Shaker Von Price Funkhouser proved an energy principle for charged black holes, research for which he won first prize at the CSU Student Research Competition in May. Funkhouser also recently published this work in Physical Review D 92 104016 (2015).
Funkhouser showed how a set of maximally charged black holes minimizes its total energy. If all charges have the same sign, this work provides the first energy interpretation of these black holes’ known static equilibrium condition, thereby replacing nearly fifty years of intuition based on forces. This intuition — that the static equilibrium is a balance between the black holes’ mutual electric repulsion and gravitational attraction — is not precise because gravity is not regarded as a force in general relativity.
Black Holes Behave Like Fluids
In their senior projects, Anthony Bardessono and Conrad Pearson are developing a correspondence between black holes and ordinary fluids. Because fluids are directly accessible in the lab, a potential future application of this correspondence is to use well-measured fluid phenomena to predict new features to explore about black holes — and perhaps about gravity itself because in general relativity, black holes represent objects that are purely gravitational and in particular exhibit very strong gravity.
Bardessono has shown how a black hole attached to a membrane interacts with the membrane like an ordinary liquid droplet that is attached to a flat surface. Depending on the type of membrane, the black hole behaves like a liquid droplet whose interaction with the flat surface is either repulsive (it beads up on the surface) or attractive (it wets the surface). Also, depending on the type of membrane, the black hole behaves like a liquid droplet that either sits on a flat horizontal surface, or hangs from it. The two cases are distinguished by the direction of the constant gravitational field that the droplet experiences.
Pearson is refining a known correspondence between a black cylinder (a cylindrical black hole) and an ordinary liquid cylinder. Just like tap water that breaks up into droplets as it falls from a faucet, a long and thin black cylinder is known to be unstable to long-wavelength perturbations. The critical wavelength (of order the cylinder circumference) corresponds well but not exactly to the critical wavelength in the Rayleigh-Plateau instability of a liquid cylinder that breaks up into droplets due to surface tension. Pearson is refining this known correspondence by incorporating the black cylinder’s self-interaction, which has been neglected in previous work, and matching the black cylinder’s instability to the instability of a fluid with elasticity (an elastic soft solid).
Themis Mastoridis's Team
Simulations Investigate Workings of High Luminosity LHC
Professor Themis Mastoridis visited the European Organization for Nuclear Research, more commonly known as CERN, in June and September for research projects on the Large Hadron Collider (LHC), High Luminosity LHC (HiLumi LHC) and the Super Proton Synchrotron.
During the summer, Mastoridis brought his CERN experience back to Cal Poly and worked with students Stan Steeper, Dylan Tucker and Devin Wieker. They investigated the performance of the HiLumi LHC’s crab cavities, devices that will lead to a significant increase of the particle collision rate and thus expedite discoveries. The students performed simulations to determine whether the crab cavities will cause any adverse effects on the accelerated particles.
Pete Schwartz's Team
Students Develop and Use Solar Cooker
Professor Pete Schwartz and three students invented and continue to develop an insulated cooking unit connected directly to a photovoltaic panel. They presented their invention at the Solar Cookers International Conference in Sacramento in July, and the food cooked using it has been “spectacular.”
The group is pursuing grants to collaboratively disseminate this technology with community partners in Rwanda and Ghana and with students in the appropriate technology classes. Next steps include involving business students in developing a sustainable business model. Anyone interested in solar cooking technology can contact Schwartz at firstname.lastname@example.org for more information.
Ryan Walter's Team
Instruments Deployed in San Luis Bay
Ryan Walter's team deploys oceanographic moorings in
San Luis Obispo Bay during summer 2015.
Professor Ryan Walter, research technician Ian Robbins, physics student Kevin Armenta and environmental science student Wesley Irons deployed oceanographic moorings in San Luis Obispo Bay during the summer. The moorings and instruments will measure nearshore physical processes, including wind-driven upwelling cycles and internal wave dynamics. Students had the opportunity to use Cal Poly's new research vessel, the TL Richards. This work was supported by an internal RSCA grant and includes collaborators from UC Davis.