Physics

Seminars in Spring 2019

All seminars are held at 4:10 PM in Phys 123, unless otherwise noted.
Refreshments will be served at 4:00 PM.

Upcoming Seminar

April 3, 2019, 4:10 PM
Thesis Talks

Jan 31

Spyridon Michalakis, CalTech
The Shape of the Quantum Realm

Time Change: 4:30 PM
Location Change: Vollum Lecture Hall

Joint Math/Physics Seminar

 At the turn of the century, a list of thirteen significant open problems at the intersection of math and physics was posted online by the president of the International Association of Mathematical Physics. But with problems such as Navier-Stokes on the list, quick progress seemed unreasonable. Indeed, a decade later, with only one problem partially solved and despite the progress yielding two Fields Medals, the list was all but forgotten. Then, in 2008, as a young mathematician at Los Alamos National Lab, I was tasked with solving the second problem on the list, which asked for a rigorous explanation of the Quantum Hall effect, an important phenomenon in physics with applications to quantum computing and beyond. The solution, which would involve a deep connection between topology and quantum physics, would come a year later. I want to share that journey with you, focusing on insights gained along the way about the relationship of mathematics to physics.

Feb 6

Kater Murch ('02), Washington University in St. Louis
Realizing a quantum Maxwell's demon with superconducting circuits

Thermodynamics is a field of physics that describes quantities such as heat and work and their relationship to entropy and temperature. Originally developed as a theory to optimize the efficiency of heat engines, two extensions of thermodynamics in the last century advanced the theory to the point at which quantum mechanics should be incorporated. First, the role of information in thermodynamics, given by Shannon, Jaynes, and Landauer, makes strong connections between heat, entropy and information. Second, extensions of thermodynamics to the realm of microscopic systems in which fluctuations are significant allow the application of thermodynamics at the level of single trajectories of classical particles. Quantum mechanics requires both of these features as information and fluctuations are central to the behavior of quantum systems. The experimental control over single quantum systems that has been achieved in this century places us in a unique position to extend thermodynamics into the quantum regime. I will describe recent experiments where we harness tools from quantum information processing with superconducting qubits to quantify the role of information in a quantum realization of Maxwell?s demon.

 

Bio: Kater received his B.A. in physics from Reed College in 2002. After that, he spent a long year slacking off, working as a bee keeper, honing his guitar skills, and studying the cello before finally starting his Ph.D. work at UC Berkeley with Prof. Dan Stamper-Kurn. After some time studying Bose-Einstein condensation in multiply connected geometries, Kater focused his interests on general problems in quantum measurement, and performed some of the first studies of position measurement quantum backaction. After receiving his Ph.D. in 2008, Kater continued work in the Stamper-Kurn group studying a possible super-solid phase of matter which occurs in spinor-Bose-Einsten condensates, and constructing a state of the art BEC apparatus. After a short postdoc in the Stamper-Kurn Group, Kater joined Irfan Siddiqi's group to study superconducting quantum circuits, where he continued to study basic questions in quantum measurement and quantum noise. In 2014, Kater joined the faculty at Washington University.  Kater has received several awards including the Alfred P. Sloan Fellowship in Physics (2015), The St. Louis Academy of Sciences Innovation Award (2017), the Cottrell Scholar Award (2018) and an NSF CAREER Award (2018).

Feb 13

Cancelled

Andrea Kunder, St. Martin's University
Our home the Milky Way Galaxy: peering into it’s center

We live in the Milky Way Galaxy — a spiral Galaxy so large, it takes 100,000 years for light to travel from one side to the other.  This light can be captured by astronomers, such as myself, using various instruments mounted to telescopes, to study the matter and structure of the stars it comes from.  We see that our Galaxy is composed of stars that are not randomly assorted, instead, they display an elegant structure that shows both order and complexity.  Here I show how we are beginning to order the stars in the deep center of the Galaxy, with the goal of piecing together the formation history of the entire Milky Way Galaxy.  I show how we have recently discovered of a separate population of stars co-existing within the inner Galaxy, possibly being one of the oldest stellar populations of the Milky Way.  This “fossil” is one of the pieces of the Galactic jigsaw puzzle.  I will conclude by showing other pieces of the Galactic puzzle being put into its proper place thanks to SMU students working within the physics group.

 

Bio: Professor Kunder received her bachelor’s degree from Willamette University and her Ph.D. from Dartmouth College. Her area of expertise is astrophysics, with more than 60 refereed scientific publications, including being an editor of an Astronomy Society of the Pacific Conference Series.  Upon completion of her PhD in 2009, she moved to Chile to work at the US National Observatory in the Southern Hemisphere, the Cerro Tololo Inter-American Observatory.  While a postdoctoral fellow at the Cerro Tololo Inter-American Observatory in Chile, she worked on improving and supporting the optical and infrared CCD imagers on the Blanco 4m telescope, as well as playing a significant role in commissioning the Dark Energy Camera (DECam).  After 4 years in Chile, she moved to the Leibniz Institute of Astrophysics (AIP) in Germany, which was previously called the Berlin Observatory, and is where Neptune was discovered.  Her work there concentrated on spectroscopic observations of Milky Way stars, and she released stellar parameters of half-a-million stars in the solar vicinity (RAVE DR5), which is the 18th highest cited paper in 2017 (out of ~24,000 refereed astronomy papers that year). Professor Kunder has been teaching at Saint Martin's University since 2017.

Feb 20

Andrew Dawes, Pacific University
Multimode Quantum State Tomography

Measuring the quantum state of a weak beam of light presents numerous challenges. Using array detection in an unbalanced homodyne configuration, we demonstrate a technique capable of measuring simultaneously the quantum state of as many as 200 individual modes at the few-photon level. This technique is being developed with an eye toward applications in characterizing systems that implement optical memory and free-space optical communication.

Bio: Andrew Dawes is an Associate Professor of Physics at Pacific University in Forest Grove Oregon where he leads a group of undergraduate research students in several fields of physics: atom cooling and trapping, pattern-forming nonlinear optics, slow- and fast-light, and the application of optical systems to quantum and classical information science. Dr. Dawes holds degrees from Duke University (PhD, 2008) and Whitman College (BA, 2002).

Feb 27

Nancy Forde, Simon Fraser University
Touching when you can't see: technologies for manipulating biology at the nanoscale

Following an introduction to relevant length scales of biological systems, I’ll talk about the nanoscale world of proteins, which function as Nature’s structural building blocks and mechanical devices.  Our group has been investigating the mechanics of a key structural protein, collagen.  I’ll focus on its flexibility and its stress response, why these properties are important and contentious, and how we have resolved some of the discrepancies in the literature. I’ll also describe our latest instrument, the mini-radio centrifuge force microscope (MR.CFM), which we have used for high-throughput investigations of collagen’s response to force.

Bio: Nancy Forde is a professor of Physics at Simon Fraser University in Vancouver, Canada. She loves what Physics can tell us about the world: why it's very difficult to snap spaghetti in two when you bend it by its ends; why coffee spills dry as a ring; and why nanoscale protein motors in our cells need to be a billion times stronger than car motors, to name just a few examples.  Her research is in the area of biophysics: her group builds instruments and manipulates proteins to help us to understand what holds us together and what can go wrong in disease.  She has been at SFU since 2004; before that, she was a postdoctoral researcher at UC Berkeley (in Molecular and Cell Biology), a PhD student at the University of Chicago (in Chemistry), and an undergraduate student at the University of Toronto (in Chemical Physics and Math).

Mar 6

Yudan Guo ('15), Stanford University
Many-body physics in Multimode Cavity QED

Ultracold atoms trapped in multimode optical resonators present new opportunities for studying interacting many-body systems. I will present our first experiment on studying photon-mediated atom-atom interactions in a confocal multimode cavity. We demonstrate the engineering of a tunable-range local interaction and a sign-changing non-local interaction. I will then show how the relative strength of the local and non-local interaction may be further controlled by addressing two degenerate resonances simultaneously. When the non-local interaction is tuned to zero, the photon-mediated interaction becomes translationally invariant in all spatial dimensions. Finally I will discuss our current effort of using such an interaction and Bose-Einstein condensate to realize a crystallized superfluid and a superfluid state with liquid crystalline properties that resembles the electronic nematic states found in strongly correlated condensed matter systems. 
Bio: Yudan Guo received his B.A. in physics from Reed in 2015. He is currently a graduate student at Stanford University. His research focuses on studying many-body physics with ultracold atoms trapped in a multimode cavity.

Mar 13

Moira Gresham ('04), Whitman College
Dark Matter Cold Fusion

Strong evidence for dark matter has existed for many years, but its identity is still unknown. After a brief overview of some of the most attractive candidates for particle dark matter, we will focus in on one intriguing possibility: dark matter nuclei that form through cold fusion. More specifically, we will explore the physics of a dark matter sector that allows for a spectrum of stable bound states of dark matter—the analog of nuclei. We will discuss the nuclear structure of these dark matter nuggets, along with a story for their potential synthesis in our Universe, highlighting parallels with the structure and synthesis of normal nuclear matter. 

Bio: Moira Gresham is Nathaniel Shipman Associate Professor of Physics at Whitman College in Walla Walla, WA. She earned a Mathematics-Physics BA from Reed College, an MA from Cambridge University, and a PhD from Caltech. She spent a year as a postdoctoral fellow at the University of Michigan in their Society of Fellows before joining the Whitman Faculty in 2011. Professor Gresham was recently honored with the Murdock Foundation’s 2018 Lynwood W. Swanson Promise for Scientific Research Award “for her influential work in theoretical particle physics and cosmology alongside her dedication to teaching and mentoring undergraduates.” She and her undergraduate research students are currently funded by her NSF grant, “RUI: Exploring Asymmetric Dark Universes”. Her favorite theorem is Noether’s Theorem.

For students interested in reading up on particle dark matter, I recommend:
For a preview of some of what I plan to talk about, check out the introduction (Sec I) in this paper:

Mar 20

Brian Smith, University of Oregon
Control and measurement of single-photon pulses

The ability to manipulate the spectral-temporal waveform of optical pulses in the classical domain has enabled a wide range of applications from ultrafast spectroscopy to high-speed communications. Extending these concepts to quantum light has the potential to enable breakthroughs in optical quantum science and technology. However, filtering and amplifying often employed in classical pulse shaping techniques are incompatible with non-classical light. Controlling and efficiently measuring the pulsed mode structure of quantum light requires efficient means to achieve deterministic, unitary manipulation that preserves fragile quantum coherences. Here an approach to deterministically modify the pulse-mode structure of quantum states of light within an integrated optical platform is presented. The method is based upon application of both spectral and temporal phase modulation to the wave packet. These techniques lay the ground for future quantum wavelength- and time-division multiplexing applications and facilitate interfacing of different physical platforms where quantum information can be stored and manipulated.

Bio: Professor Brian J. Smith received his undergraduate degrees in physics and mathematics from Gustavus Adolphus College, and his PhD in Physics from the University of Oregon. He spent 10 years at the University of Oxford, where he held positions as a post-doc, a Senior Research Scientist, and an Associate Professor. Professor Smith is currently an Associate Professor of Physics at the University of Oregon. His research interests lie in the general areas of quantum optics and quantum technologies, and their use in probing fundamental quantum physics and realizing quantum-enhanced applications with performance beyond that possible with classical resources.

Apr 3

Thesis Talks

Apr 10

Thesis Talks

Apr 17

Thesis Talks

Apr 24

Thesis Talks

May 1

Thesis Talks