USF Physics and Astronomy Colloquium Series

The Physics and Astronomy Colloquia at the University of San Francisco are talks given by invited research scientists, on topics of current interest. The Physics Colloquium Series has been in place since 1994.

All colloquia typically start at 11:45, and will have light refreshments served. Colloquia take place in CS 303, unless otherwise noted.

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Professor Douglas Osheroff (middle), 1996 Nobel Laureate in Physics, appears here on the occasion of his colloquium at USF, flanked by Professors Camblong (left) and Camperi (right).

PAST COLLOQUIUM SERIES VIDEOS

Fall 2013 Colloquium Series

October 3, 2013 - Dr. Chris Weber

"The Strangely Rapid Diffusion of Electrons in Magnetic and Non-Magnetic Semiconductors"

11:45-12:55 in LCSI 303

Ultrafast optical measurements of diffusivity probe material properties of both practical and fundamental importance: diffusion currents of electrons or holes play an important role in the operation of many semiconductor devices, while the Einstein's relation connects a particle's diffusivity to its mobility and its density of states. The magnetic semiconductor (Ga, Mn)As could play an important role in spintronic technology, but still poses vexed questions about the role of charge carriers in its magnetism. The incorporation of magnetic manganese into GaAs introduces significant disorder; nonetheless, our ultrafast measurements show charge carriers diffusing as quickly as they would in pristine GaAs, and show that the conduction-band density of states is unaffected by Mn. These findings may hold clues to the nature of magnetism in (Ga,Mn)As. In a related p-type semiconductor, our measurements of indium phosphide also show rapid diffusion of photoexcited carriers, enhanced markedly by Pauli repulsion as the photoexcited density increases. I will explain why, although this enhancement is in principle expected, prior measurements of p-type semiconductors have always shown the opposite trend.

Dr. Weber received his BA and PhD degrees in Physics from UC Berkeley. Since 2008, he has been an Assistant Professor of Physics at Santa Clara University.

October 11, 2013 - Dr. Tristan Smith

"Cosmology After the Planck Satellite"

11:45-12:55 in LCSI 210

In the (relatively) short span of 40 years, cosmology has transformed from a purely theoretical field to one overflowing with increasingly precise data. As a result, our picture of how the universe came into being and how it evolves has come into near-perfect focus: it seems as though, after thousands of years of thought, we may be a few short decades away from understanding the nature of our ultimate origins. Recently an exquisite set of observations taken by the Planck Satellite has made our image of the early universe significantly crisper. These data have confirmed most of our standard cosmological models, but at the same time has raised some intriguing new questions. I will review our basic understanding of cosmology and describe how the Planck Satellite has both confirmed and challenged our understanding of the universe.

Dr. Smith received his PhD in Theoretical Physics from the California Institute of Technology and conducted a postdoctoral fellowship at UC Berkeley. He is currently a visiting professor of Theoretical Physics at Swarthmore College.

October 17, 2013 - Dr. Daniel Garcia

"From Academia to Industry: A Physicist in the Private Sector"

11:45-12:55 in LCSI 303

For a significant number of students earning a bachelors, masters, or PhD in Physics, their career path will lead them in the private sector and towards industry jobs. However, many physics students are more familiar with an academic trajectory as their primary career path. The purpose of my talk is to further illuminate the career path of an industry physicist working for a major tech company, specifically Intel Corporation. I will give a brief overview to the significant technological accomplishments we have made over the last decade of research and development. Then I will transition specifically to my own journey, starting as an experimental condensed matter physicist doing research in correlated electronic systems and eventually leading to the research and development I am currently involved with, in the area of chemical mechanical planarization (CMP) and process control.

Dr. Garcia is currently a Senior Process Engineer at Intel Corporation. He received his BS in Physics from MIT and his PhD in Physics from University of California, Berkeley.

October 24, 2013 - Dr. Brandon Brown

"Quantum by No Solace: the Life and Work of Max Planck"

11:45-12:55 in LCSI 303

The German physicist Max Planck (1858-1947) is known as the Father of Quantum Theory, and his name adorns scores of institutes, endowments, and now a scientific mission aiming to probe the universe's initial conditions. But one finds very little in the English language concerning his actual work and his fascinating life. After digging through a variety of sources and archives, I offer a taste of both, including his unique mindset that lead to the beginning of quantum theory, as well as a poignant life interwoven with figures like Albert Einstein and Adolf Hitler.

Dr. Brown is a Professor of Physics at the University of San Francisco.

November 8, 2013 - Dr. Dieter Hoffmann

"Physicist, Atomic Spy, Communist: the Three Lives of Klaus Fuchs (1911-1988)"

11:45-12:55 in LCSI 210

The name Klaus Fuchs is commonly associated with one of the most consequential cases of scientific espionage: the passing of secrets from the US-American Bomb Project to the Soviet Union in the 1940s. But the atomic spy is only one facet of the life story of Klaus Fuchs. As a communist, he had to flee from Nazi Germany in 1933, and during his exile in Britain, he developed into one of the most talented physicists of his generation, taking part in the Manhattan Project as a member of the British committee. In 1950, he was sentenced to prison for his espionage, and after his release, he moved to communist East Germany, where he started a second career in the 1960s as a physicist and a science manager.

Dr. Hoffmann is a Research Fellow at the Max Planck Institute for the History of Science and adjunct Professor at the Humboldt University in Berlin.

November 14, 2013 - Dr. Fernando Perez

"iPython: an Architecture for Interactive Scientific Computing Across Languages"

11:45-12:55 in LCSI 303

IPython is an environment for interactive and parallel computing that began its life back when the author was a graduate student in Physics, looking for a way to reduce the number of languages he needed to juggle for his everyday research needs. Today, it has grown into a large and active open source effort embedded in the Scientific Python ecosystem, a collaborative endeavor where many scientists create the tools they need to enable better research. IPython provides the user-centered environment for interacting with computational resources, with classic shell-like tools, high-level parallel computing libraries and a web-based notebook that combines computations with rich text, mathematics and any kind of multimedia elements that modern web browsers can display. IPython supports all stages in the life-cycle of a scientific idea: individual exploration, collaborative development, large-scale production using parallel resources, publication and education. The IPython Notebook allows scientists to share their work in an open document format that is a true 'executable paper': notebooks can be version-controlled, exported to HTML or PDF for publication, and used for teaching. IN this talk, I will describe how a single, coherent architecture covers this entire use spectrum, providing an environment where the working scientist can explore data, run production analyses, and share results, including multiple programming languages as needed.

Dr. Perez is a research scientists at the UC Berkeley Brain Imaging Center. He received his PhD in Physics from the University of Colorado and conducted postdoctoral work in Applied Mathematics.

November 26, 2013 - Dr. Beth Reid

"Mapping and Measuring the Universe with Galaxy Redshift Surveys"

11:45-12:55 in LCSI 303

I'll assume no prior knowledge of cosmology and walk through how we use maps of the universe (2d maps from the cosmic microwave background and 3d maps of galaxy redshift surveys) to measure the expansion history of the universe and the rate at which gravity is coalescing matter in the universe. With both measurements in hand, we can hope to address the question of whether the observed cosmic acceleration is due to an exotic, negative pressure fluid dominating the energy budget of the universe, or signaling a breakdown of general relativity.

Dr. Reid received her PhD degree in Physics from Princeton and conducted postdoctoral work at the Institute for Space Sciences (ICC) in Barcelona. She is now a cosmology data science fellow at the Berkeley Center for Cosmological Physics.