Physics Colloquium

DEPARTMENT OF PHYSICS & ASTRONOMY COLLOQUIUM SERIES

Colloquia are held on Friday afternoon at 3:15 pm,
in Bennett Hall, Room 140, unless otherwise noted

Refreshments are provided before the Colloquium talk

Spring 2020

Schedule so far:

POSTPONED DUE TO WEATHER; RESCHEDULE DATE TBD. February 7: Ziad Ganim, Yale U., Chemistry, “Stretch ’em till they stop blinking: Single molecule force microscopy of fluorescent macromolecules”
- Joint with UMaine Medicine (part of the UMaine Medicine seminar series)

February 14: Bethany Wilcox, U. Colorado Boulder, “Scalable and flexible measures of student learning across time and context”
- Physics education researchers have a long history of examining students’ knowledge of physics content in order to understand, and ultimately improve, students’ learning. Historically, many of these investigations have targeted students understanding of a specific concept or topic within the context of a particular course in the physics curriculum at a single institution. This includes quantitative studies designed to measure students’ learning using validated conceptual diagnostic exams. However, studies of how students’ ideas and reasoning change over time and across different physics contexts has been less well examined. Here, I will also present work aimed a developing scalable and flexible conceptual assessments designed to provide quantitative, meaningful comparisons of student learning across different contexts, instructors, and institutions. This new model for assessments utilizes advances in online administrative platforms to facilitate sustainable and scalable administration of these assessments to a broad student population.

February 21: Glen Van Brummelen, Quest U., “The Forgotten Man: Astronomy in the Transformative 15th Century”
NOTE LOCATION: Hill Auditorium, ESRB
Joint with the Department of Mathematics and Statistics
- We know a lot less than we think. The history of mathematics is partly a record of what happened, but uncomfortably more than we might expect, over the decades it has also been a record of what we care about. We will explore one episode that illustrates the “forgotten” history of mathematics, in early 15th-century mathematical astronomy. The forgotten man is Giovanni Bianchini, the CFO from Ferrara who turned his eye away from bookkeeping and toward the heavens. His unusual path to academia provoked a number of revolutions, including among others the birth of the European tangent function. Overlooked in the shadow cast by his now more illustrious successor Regiomontanus, Bianchini’s role in the history of mathematics and science fully deserves a resurrection.

March 27: Seth Campbell, U. Maine, Earth and Climate Sciences and Climate Change Institute, Thwaites Glacier Project
April 3: Mikhail Zamkov, Bowling Green State U., Quantum dot spectroscopy
April 10: David Smith, U. Washington, Introductory Physics for the Life Sciences
April 24: Trevor Smith, Rowan U., Quantitative analysis of diagnostic assessments in physics
May 1: Senior capstone presentations

Fall 2019

September 6: No colloquium; Department Picnic
September 13: Kevin Plaxco, U. California Santa Barbara, “Counting Molecules, Dodging Blood Cells: continuous, real-time molecular measurements directly in the living body”
- The availability of technologies capable of tracking the levels of drugs, metabolites, and
  biomarkers in real time in the living body would revolutionize our understanding of health and
  our ability to detect and treat disease. Imagine, for example, a dosing regime that, rather than
  relying on your watch (“take two pills twice a day”), is instead guided by second-to-second
  measurements of plasma drug levels wirelessly communicated to your smartphone. Such a
  technology would likewise provide researchers and clinicians an unprecedented window into
  neurology and physiology, and could even support ultra-high-precision personalized medicine in
  which drug dosing is optimized minute-by-minute using closed-loop feedback control. Towards
  this goal, we have developed a biomimetic, electrochemical sensing platform that supports the
  high frequency, real-time measurement of specific molecules (irrespective of their chemical
  reactivity) in situ in the bodies of awake, freely moving subjects.
September 20, 3:00 start: Alexander Turbiner, ICN-UNAM & Stony Brook U., “Choreography in Physics, in (non)-Newtonian gravity (living in motion)”
October 4: Christopher Spalding, Yale: “Primordial Sculpting of Planetary System Architectures”
- The census of extrasolar planets detected continues to grow well into the
  thousands. With this number, we transition from the age of discovery, and move toward
  the age of characterization. Specifically, a growing set of exoplanetary systems have
  emerged as exhibiting large orbital misalignments with respect to both other planets in
  the system, and with respect to the host star’s spin axis. In contrast, our Solar system
  exhibits small inclinations and the Sun’s spin axis is well-aligned. In this talk, I explore
  the hypothesis that the ultimate 3-dimensional architectures of planetary systems is
  largely set by physical mechanisms playing out during the opening 10-100 million years
  of planetary system evolution. I will show how the stellar quadrupole moment of young
  stars may destabilize planetary systems, and how nearby stars may tilt entire systems
  by over 90 degrees. I discuss tests of these hypotheses promising to emerge within
  upcoming datasets, and important lessons that looking upwards have revealed about
  our own planet’s history.
October 11: Scott Randall, Harvard-Smithsonian Center for Astrophysics, “X-Ray Studies of Clusters of Galaxies”
- Twenty years after its launch, Chandra remains the highest angular
  resolution X-ray observatory ever constructed. This resolution, combined with a
  relatively large effective area and a predictable instrumental background, have allowed
  significant advancements covering a wide range of astrophysical topics, including the
  co-evolution of supermassive black holes and their host galaxies, black hole accretion,
  supernovae and their progenitors, the interiors of neutron stars, the evolution of
  massive stars, the interaction of exoplanets and their stars, the physics of galaxy
  clusters, the nature of dark matter and dark energy, and the evolution of the universe
  itself. I will pay particular attention to what Chandra has helped us learn about AGN
  feedback, galaxy clusters, and the nature of dark matter. I will also briefly discuss the
  outlook for X-ray astronomy over the coming decade and beyond.
October 25: Feng Yan, U. Alabama: “Photovoltaics for Renewable Energy: Cubic and Non-Cubic Chalcogenides Thin Film Solar Cell”
- Photovoltaic (PV) materials and devices, commonly known as solar cells, directly convert sunlight into electrical energy, is one of the most efficient renewable energy systems. Chalcogenides thin films solar cells dominate the thin-film solar cells markets. Cubic CdTe thin-films are today’s dominant thin-film technology in the photovoltaic industry. The efficiency of thin-film CdTe solar cells has increased from 17% five years ago to 22% now, surpassing the market-dominant multi-crystalline Si technology. Several technology components have contributed to the sudden rise in efficiency. This seminar overviews the recent learning on new functional layers added to CdTe films to boost the device performance. Also, a new type of non-cubic chalcogenides materials with quasi-one-dimensional ribbons provide unique carrier transport pathway to suspend the drawback in cubic chalcogenides thin-film solar cells can achieve 7% in our lab. With the learning from cubic CdTe and the theoretical calculation, a new type of thin films solar cells could be integrated into the high throughput manufacturing.
November 15: Emanuele Berti, Johns Hopkins U., “Gravitational waves from compact binaries: implications for fundamental physics and astrophysics”
- The observation of compact binary mergers by the LIGO/Virgo collaboration marked the
  dawn of a new era in astronomy. The space-based detector LISA will fulfill this vision by
  opening a new observational window at low frequencies. The gravitational radiation
  emitted by compact binaries encodes important information on their astrophysical
  formation mechanism. Furthermore, compact objects – whether in isolation or in binaries
  – are excellent astrophysical laboratories to probe our understanding of high-energy
  physics and strong-field gravity. I will discuss how gravitational wave detectors can
  further our understanding of the formation and evolution of compact binaries, test
  gravity in the strong field regime, and look for smoking guns of new physics.
December 6: Karissa Tilbury, U. Maine Biomedical Engineering