====== Sign-up for Informal Talk with Colloquium Speaker ====== Light lunch will be provided by the department at 12:45pm, and the speaker will show up around 1:15pm. Each event will be hosted by a student representative. If you would like to participate in the lunch (up to 15 students per date), or be the student host (see description of duties below), please sign up by editing the table. You can edit only after you log on with your physics account ID and password. The log on button is near the right bottom of this page. For more detailed information about each speaker, click on the speaker's name, visit [[http://www.physics.umn.edu/calendar/PAC/semester|Colloquium Schedule]] or check below (or links in the box on the right titled "Table of Contents." **Host student**: We need one of the participants to volunteer to be the host to make sure things go smoothly. If you are the host, you will get the food, drinks, plates and napkins from Shelley Frankel (314) and bring it to 216 before the other students arrive at 12:45. If Wendy is not at her desk, the food will be in the minifridge at the back of the office (towards the windows) on your left. It may be helpful to discuss what types of questions you'd like to ask the speaker before he/she arrives. When the speaker gets there, introduce yourself and make sure the conversation gets started! If you are willing to play this role, please move your name from "participants" column to the "host" column. **The faculty host** is responsible for the entire visit schedule of the speaker. If one of the students makes sure that s/he is aware that 1 to 1:45pm is set aside for the speaker to meet with the students, it would be useful in case the faculty host forget to do this. ^Date^Speaker (click name for more detail info)^Topics^Faculty host^Host (click name if you want to Email the host)^Participants^ |1/30|[[#january_30|Seth Shostak]], SETI Institute|When Will We Discover the Extraterrestrials?|?|?|Just show up for pizza. **Thursday**, not Wednesday, from 11:45am to 1pm| |2/6|[[#February_6|Cary Forest]], University of Wisconsin, Madison|Laboratory experiments on magnetic field dynamos|?|Scott Thaller|Kimia Ghanbeigi, Lee Wienkes| |2/13|[[#February_13|Michael Marder]], University of Texas, Austin|Rising above the gathering storm with U Teach|?|Jen Docktor|Kimia Ghanbeigi| |2/20|[[#February_20|Richard Ellis]], Cal Tech|The Case for a Significant Population of Sub-Luminous Star Forming Galaxies at Redshift 10|Liliya Williams|?|Pearl Sandick, Matt Sexton, Jimmy Erickson, Barun Dhar, Kevin Klapoetke, Katie Leonard, Eric Rosenberg, Josh Ellis| |2/27|[[#February_27|Ray Bishop]], University of Manchester|Confronting The Quantum Many-Body Problem: An Overview Of The Coupled Cluster Method And Its Applications In Physics|Charles Campbell|Yaroslav Lutsyshyn| | |3/5 3/6|[[#March_5|David Gross]], Kavli Institute for Theoretical Physics, UCSB| **Van Vleck Lectures** the meeting time will be **Thursday (3/6) between 2:30 and 3:30pm** in room 216.|Goldman|Pearl Sandick|Yaroslav Lutsyshyn, Yun Chen, Burak Himmetoglu, Alex Levchenko, Sergiy Dubynskiy, Jin Chen, Meng-Ru Wu, Emir Gumrukcuoglu, Matt Sexton, Ivan Gordeli | |3/12|[[#March_12|David Charbonneau]], Harvard|Extra Solar Planets|Shaul Hanany|?|Matthew Strait, Josh Ellis, Jimmy Erickson, Katie Leonard, Barun Dhar, Lynn Wilson, Michael Milligan, Dan Polsgrove | |3/19|Spring Break||||| |3/26|[[#March_26|J.V. Porto]], NIST| "Controlled exchange interactions in a double-well optical lattice." |E.Dan Dahlberg|?| Hannes Hubmayr, Stephen Snyder, Lee Wienkes, Yaroslav Lutsyshyn, Te-Yu Chen, Yu Chen, Yen-Hsiang Lin| |4/2|[[#April_2|Saskia Fischer]], University of Bochum||E.Dan Dahlberg|?|Lee Wienkes, Yu Chen, Stephen Snyder, Jimmy Erickson, Katie Leonard, Mun Chan, Eric Garlid, Mike Erickson, Tsuyoshi Kondo, Dan Ouellette, Tanner Schulz, Feng Guo, Tao hu, Greg McKusky| |4/9|[[#April_9|Martin White]] - UC Berkeley|Cosmology|Shaul Hanany|?|Matthew Strait, Susan Dorsher, Hannes Hubmayr, Michael Milligan, Dan Polsgrove, Josh Ellis, Jimmy Erickson, Katie Leonard, Ilan Sagiv| |4/16|[[#April_16|John Martinis]], UCSB| ? |E.Dan Dahlberg|?|Yaroslav Lutsyshyn, Joe Kinney, Lee Wienkes, Feng Yi,Shun Wang, Yu Chen, Stephen Snyder, Tao Hu, Eric Garlid, Te-Yu Chen, Mun Chan, Mike Erickson, Dan Ouellette| |4/23|[[#April_23|Ramon Lopez]], University of Texas, Arlington|Space Weather|Kenneth Heller|?|Jesse Woodroffe, Michael Milligan, Dai Lei, Lynn Wilson,Scott Thaller, Jimmy Erickson, Katie Leonard, Dustin Lorshbough | |4/30|[[#April_30|Kam-Biu Luk]], University of California, Berkeley|Reactor Experiments for Neutrino Oscillations|Kenneth Heller|?|Matthew Strait, Susan Dorsher, Alexander Monin, Jen Docktor| |5/7|[[#May_7|G. J. Wasserburg]], Cal Tech|Imagination, pulp fiction, science & exploration|Yong Qian|?|Matthew Strait, Josh Ellis, Jimmy Erickson, Katie Leonard, Jen Docktor| ===TO SIGN UP: After you log in using the button at the bottom with your physics account ID and password, use the "Edit" button on the right and enter your name on the appropriate date. If you don't see the "Edit" button, you are not logged in. --->=== ====== Colloquium schedule and some information about the speakers ====== ==== January 30 ==== Speaker: **Seth Shostak**, SETI Institute; faculty host, **Cushman**\\ Subject: **When Will We Discover the Extraterrestrials?**\\ **Abstract:** The scientific hunt for extraterrestrial intelligence is now into its fifth decade, and we still haven't uncovered a confirmed peep from the cosmos. For that matter, we still don’t know if life – at any level of intelligence – exists beyond Earth. Could this mean that finding aliens, even if they’re out there, is a project for the ages – one that might take centuries or longer?\\ New technologies and new strategies for use in the search for extraterrestrial biology suggest that, despite the continued dearth of hard evidence for life elsewhere or signals from other societies, there is good reason to expect that success might not be far off – that within a few decades we might find evidence of sophisticated civilizations.\\ Why this is so, what contact would tell us, and what such a discovery would mean, are the subject of this talk on the continuing efforts to establish our place in the universe of thinking beings.\\ **[[http://www.seti.org/about-us/people/staff/shostak-seth.php|Background:]]** Seth is an astronomer with a BA in physics from Princeton and a PhD in astronomy from Caltech, and is involved with the Institute's SETI research. But he's also responsible for much of the outreach activities of the Institute. He is science editor for "The Explorer", gives more than 50 talks annually for both academic and general audiences, and writes magazine articles (and books) about SETI. He also teaches informal education classes on astronomy and other topics in the Bay Area, and is the inventor of the electrical banana, a circumstance he claims has had little positive effect on his life. He is the host for the SETI Institute's weekly radio program Are We Alone?\\ Before coming to SETI, Seth did research work on galaxies using radio telescopes at observatories and universities in America and Europe. His avocations include photography, filmmaking, and electronics.\\ Seth has produced a series of lectures on tape and video on the subject of SETI. For more information visit the [[http://www.teach12.com/ttc/assets/coursedescriptions/146.asp|Teaching Company]] website. ==== February 6 ==== Speaker: **Cary Forest, University of Wisconsin, Madison**\\ Subject: **Laboratory experiments on magnetic field dynamos**\\ **Abstract:**\\ **Background:** * 1992 Ph.D. Princeton University, Astrophysical Sciences, Program in Plasma Physics * 1986 B.S. University of Wisconsin, Applied Mathematics, Engineering and Physics My research focuses on understanding how electrical currents (and hence magnetic fields) are generated in fusion plasmas and in turbulent flows of liquid metals. I am an experimentalist, which means that I build devices and carry out experiments on these devices to answer fundamental questions like: * Where do the magnetic fields found on planets and stars come from? * How can magnetic fields be used to confine hot plasmas and create a burning star on Earth? One of my experiments, the Madison Dynamo Experiment, uses a 300 gallon liquid sodium facility to study how magnetic fields are generated in turbulent flows of liquid metal (like the conditions found in the core of the Earth). The experiment uses two 100 Hp motors to drive flows in a spherical container that are expected to lead to self-generation of magnetic fields. My fusion research is carried out on the Madison Symmetric Torus where confinement and stability of a toroidal magnetic configuration known as the reversed field pinch is carried out. My research on MST focuses on studies of current transport, electron heat transport and microwave heating of electrons (to drive current) in the RFP geometry. I recently spent a year on sabbatical in Germany working on the ASDEX-U tokamak, studying similar questions on a large tokamak. I also direct research on a smaller, basic plasma physics experiment investigating the MHD stability of a line-tied screw pinch plasma. The experiment was constructed to test the hypothesis that two conducting shells, one rotating with respect to the first, can stabilize current driven kink modes in fusion plasmas. The experiment is also providing data about stability a geometry which is strikingly similar to the geometry of solar eruptions (solar flares or coronal mass ejections).\\ ==== February 13 ==== Speaker: **Michael Marder, University of Texas, Austin** Faculty host: **Ken Heller**\\ Subject: **Rising above the gathering storm with U Teach**\\ **Abstract**:A report called Rising Above the Gathering Storm gathered an unusual amount of attention when the National Academy released it in 2007, and its conclusions have guided discussion in Washington DC and elsewhere since. The report makes the case that the future of the country depends upon strengthening the national infrastructure for mathematics and science, and particularly emphasizes the importance of improving science and mathematics education in public schools. I began working to improve teacher education in mathematics and science at UT Austin in 1997 with a program called UTeach. We were highlighted in the Gathering Storm report, and are now the nucleus of a national effort. I will describe data from across the nation indicating the scope of the problem we face if we wish to increase access of citizens from many economic and demographic groups to mathematics and science. Then I will describe the steps we took at UT Austin, the accomplishments that generated national attention, and some of the problems that are still unsolved. ==== February 20 ==== Speaker: **Richard Ellis (Caltech)**; faculty host, **Williams**\\ Subject: **The Case for a Significant Population of Sub-Luminous Star Forming Galaxies at Redshift 10**\\ **Abstract**: Locating and characterizing the sources responsible for cosmic reionization and ending the so-called "Dark Ages" is a new frontier in theoretical and observational astronomy. A popular view is that, a few hundred million years after the Big Bang, a high density of low mass star forming galaxies were produced. Finding and studying such faint sources is a major driver for future facilities such as the James Webb Space Telescope and the proposed Thiry Meter Telescope. Meanwhile, by harnessing the strong gravitational lensing power of massive clusters, the first candidate sources beyond z=7 are being found and studied. I will describe the progress (and limitations) of the work we are doing with Keck, Spitzer and Hubble in this area which provides a first tentative glimpse of the Universe at redshift 10.\\ **Background**: http://www.astro.caltech.edu/~rse/ I am working primarily in observational cosmology addressing issues related to the nature of the world model, the origin and evolution of galaxies, the growth of large scale structure and the nature and distribution of dark matter. I am enthusiastic about the use of new instruments and observational opportunities when they further the progress that can be made in these areas. ==== February 27 ==== Speaker: **Ray Bishop, University of Manchester**; faculty host: **Campbell**\\ Subject: **Confronting The Quantum Many-Body Problem: An Overview Of The Coupled Cluster Method And Its Applications In Physics**\\ **Abstract:** Examples of quantum many-body systems abound in Nature. Thus, it is clear that in fields like molecular, solid-state, and nuclear physics most of the fundamental objects of discourse are interacting many-body systems. But even in elementary particle physics one is usually dealing with more than one particle. For example, at some level of reality a nucleon comprises three quarks interacting via gluons and surrounded by a cloud of mesons, which are themselves made of quark-antiquark pairs. Even more fundamentally, even the “physical vacuum” of any quantum field theory is endowed with an enormously complex infinite many-body structure due to virtual excitations. A key central role in modern physics is thus occupied by quantum many-body theory, where we are especially interested in the possible existence of any universal techniques that are powerful enough to treat the full range of many-body and field-theoretic systems. One such method is the coupled cluster method. This has become one of the most pervasive (possibly the most pervasive), most powerful, and most successful of all fully microscopic formulations of quantum many-body theory. It has probably been applied to more systems in quantum field theory, quantum chemistry, nuclear, subnuclear, condensed matter and other areas of physics than any other competing method. It has yielded numerical results which are among the most accurate available for an incredibly wide range of both finite and extended systems on either a spatial continuum or a regular discrete lattice. In this talk I aim to give an overview of the method itself and some illustrative examples of its power and range of applicability.\\ **Background**: http://www.theory.physics.manchester.ac.uk/people/index.php?doc=bishop\\ Research Interests * development of techniques of microscopic quantum many-body theory (especially the coupled cluster method), and their applications to * the structure of light and intermediate-mass atomic nuclei * lattice and continuum quantum field theories * spin-lattice systems in quantum magnetism * strongly correlated electronic systems * systems in quantum optics, quantum electronics and solid-state optoelectronics * strongly correlated fermion/boson systems * quantum coherence and quantum information theory * generalised pure coherent states * new classes of mixed coherent states (including thermal coherent states) * noisy bases in Hilbert space * coherence/decoherence phenomena * generalised thermofield dynamics * extended quantum phase space methods ==== March 5 ==== **Van Vleck Public Lecture in 150 Physics**\\ **Also, March 6, Physics colloquium**\\ Speaker: **David Gross, Kavli Institute for Theoretical Physics, UCSB**; faculty host: **Allen Goldman**\\ Subject: To be announced\\ **Abstract**\\ **Background** http://www.kitp.ucsb.edu/kitpnews/item/?id=15\\ David J. Gross, director of the Kavli Institute for Theoretical Physics (KITP) and the first incumbent of the Frederick W. Gluck Chair in Theoretical Physics at the University of California at Santa Barbara, has been awarded the 2004 Nobel Prize in Physics for solving in 1973 the last great remaining problem of what has since come to be called "the Standard Model" of the quantum mechanical picture of reality. He and his co-recipients discovered how the nucleus of atoms works. Gross shares the prize with Frank Wilczek, now a physics professor at Massachusetts Institute of Technology, who was Gross's graduate student at Princeton University, when the pair completed the calculation that resulted in the discovery for which they have received the Nobel Prize. The other recipient, H. David Politzer, a physics professor as the California Institute of Technology, was working independently on a similar calculation. Gross and Wilczek and independently Politzer made the key discovery of how the "strong" force works to bind the constituent elements, called quarks, of protons and neutrons (the particles that make up the nucleus of atoms). The other three forces of nature--electromagnetism, the weak force (responsible for radioactive decay), and gravity all diminish in strength with distance. They discovered that the strong force grows stronger with distance. This discovery called "asymptotic freedom" means that attempts to pull the quarks inside protons and neutrons apart increase the strength of the force binding them. This finding has had enormous implications for the design and conduct of experiments at the world's large accelerator facilities because it has enabled physicists to calculate what the results of the experiments should be. Discrepancies from those calculated results in turn provide the invaluable clues to new physics—i.e., physics beyond the Standard Model.\\ ==== March 12 ==== Speaker: **David Charbonneau (Harvard)**; faculty host: **Hanany**\\ Subject: **Extra Solar Planets**\\ **Abstract**\\ **Background**: http://cfa-www.harvard.edu/~dcharbon/frames.html \\ Welcome to the realm of extrasolar planets.\\ The Era of Comparative Exoplanetology David Charbonneau Harvard-Smithsonian Center for Astrophysics When extrasolar planets are observed to eclipse their parent stars, we are granted unprecedented access to their physical properties. It is only for these systems that we are permitted direct estimates of the planetary masses and radii, which in turn provide fundamental constraints on models of their physical structure. Furthermore, such planets afford the opportunity to study their atmospheres without the need to spatially isolate the light from the planet from that of the star. I will review the most recent results, and then describe a new observatory that will survey 2000 nearby low-mass stars with a sensitivity to detect rocky planets orbiting within their stellar habitable zones. ==== March 26 ==== Speaker: **J.V. Porto, NIST**; faculty host: **Dahlberg**\\ Subject: to be announced\\ **Abstract**: \\ **Background**: http://www.nist.gov/public_affairs/releases/quantum_gate.html\\ Physicists at the Commerce Department’s National Institute of Standards and Technology (NIST) have induced thousands of atoms trapped by laser beams to swap “spins” with partners simultaneously. The repeated exchanges, like a quantum version of swinging your partner in a square dance but lasting a total of just 10 milliseconds, might someday carry out logic operations in quantum computers, which theoretically could quickly solve certain problems that today's best supercomputers could not solve in years. **Patterned Loading of Atoms into an Optical Lattice** http://physics.nist.gov/TechAct.2002/Div842/div842.html Quantum systems, such as individual atoms, can be used as bits of information. The processing of such information, governed by the rules of quantum mechanics, is called quantum computing. There is currently great interest in realizing a quantum computer, which is predicted to require exponentially less effort than a classical computer to solve certain large-scale problems, such as factoring large numbers. "Controlled exchange interactions in a double-well optical lattice." The internal spin states of individual neutral atoms are nearly ideal candidates for quantum bits. One key requirement for quantum logic is the ability to generate controlled, state-dependent interactions between qubits. I will describe experiments in a double-well optical lattice where we isolate and control arrays of pairs of rubidium atoms. Using this lattice we can merge pairs of atoms into the same lattice site, resulting in the required spin-dependent exchange interactions. In addition, we demonstrate how to use light to address atoms spaced below the optical diffraction limit. These basic tools could form the physical basis for a number of recent proposals for quantum information processing that rely heavily on parallel operations. seminar: "Cold atoms in optical lattices: the 2D Mott insulator and a new approach to optical lattice engineering." I will describe two sets of experiments using ultra cold atoms in optical lattices. In one, we accurately measure the condensate fraction in a 2D Bose-Hubbard system as a function of the lattice depth and compare to theory. In the other, we demonstrate a method of adiabatically dressing spin-dependent lattices, a technique that can in principle generate non-trivial sub-wavelength structure. Non-adiabatic spin-flip loss is one of the limiting processes in this lattice, and we measure spin-flip loss under a variety of conditions. We are developing a processor for quantum information, using neutral atoms trapped in an optical lattice as the quantum information register. In an optical lattice, atoms are trapped in the periodic intensity pattern formed from the interference of intersecting laser beams. In order to achieve the best performance for quantum information processing, we would like atoms tightly confined, which can be achieved with a short-period optical lattice. However, to initialize and read out the quantum register, we would like atoms in sites spaced more than an optical wavelength apart. We have taken a major step towards achieving this goal by loading every third site of a one-dimensional, short-period optical lattice with atoms from a rubidium Bose-Einstein condensate. ==== April 2 ==== Speaker: **Saskia Fischer, University of Bochum**; faculty host: **Dahlberg**\\ Subject: to be announced\\ **Abstract**: \\ **Background**: Institute for Materials and nanoelectronics\\ ==== April 9 ==== Speaker: **Martin White - UC Berkeley**; faculty host: **Hanany**\\ Subject: **Cosmology**\\ **Abstract**\\ **Background**: http://astro.berkeley.edu/~mwhite/myresearch.html \\ I am a theorist and phenomenologist. While I originally trained in Particle Physics, in the last few years my interest has centered around the question of the formation of galaxies and structure in the universe. How did it originate, what were the forces responsible for making it what it is today and what can it teach us about the universe? I am particularly interested in using cosmology to learn about the nature of the dark energy believed to be causing the expansion of the universe to accelerate, and in the formation and evolution of galaxies and large-scale structure. Cosmology today is in a state similar to where particle physics was 20 years ago. The big picture is in place, but many of the fundamental questions remain unanswered. With the tremendous growth in computational and observational power, cosmology is a rapidly moving and fairly young field and can also be quite competitive. I am a member of the Theoretical Cosmology group. My work involves both analytical and numerical components, with some simulations (and data-analysis). The basic framework is (general) relativistic perturbation theory and quantum field theory, plus some simple radiative transfer and fluid mechanics. While the study of structure formation is a unifying concept, my research falls into three separate categories: * Cosmic Microwave Background * Numerical simulations of structure formation * Large-Scale Structure * Galaxy formation and evolution ==== April 16 ==== Speaker: **John Martinis, UCSB** faculty host: **Dahlberg** \\ Subject: to be announced\\ **Abstract** \\ **Background**: http://gabriel.physics.ucsb.edu/~martinisgroup/ \\ Josephson Junction Quantum Computing at UCSB Our research goal is to build a quantum computer using superconductors. Much of our effort is devoted to understanding the basic physics of decoherence (error) mechanisms in Josephson junction devices. Pictured below is a wafer with test dies that we use to measure two-qubit logic gates. Entanglement of Josephson-Junction Quantum Bits John Martinis, UC Santa Barbara The Josephson junction is an ideal solid-state system for building "electrical atoms" that can function as quantum bits for a quantum computer. Recent advances in the materials and design of phase qubits have dramatically improved their coherence so that high-fidelity quantum logic operations can be performed. Combined with advances in microwave electronics, full characterization of single and coupled qubit logic gates are now possible using quantum tomography techniques. I will report on several recent experiments of our group demonstrating tomographic state measurement of single and coupled qubit logic gates that provides direct proof of entanglement. I will also discuss new experimental results where Fock states (photon number states) were generated in an electrical resonator. Magnetism in Superconducting Devices at Millikelvin Temperatures John Martinis, UC Santa Barbara I will discuss a recent experiment where the flux threading a dc SQUID was measured to change with a 1/T temperature dependence, characteristic of the paramagnetic response of electron spins. With the magnitude of the effect being proportional to the density of trapped vortices, this data is compatible with the thermal polarization of surface spins in the trapped fields of superconducting vortices. In the absence of trapped flux, the surface spins also show evidence of 2-D spin-glass freezing at a temperature below about 100 mK. These results suggest that surface spins are present on metals with a density of about 1/nm2; however, the microscopic origin of the spin states are currently unknown. It also suggests an explanation for the "universal" 1/f flux noise observed in SQUIDs that has not been understood for 20 years. This experiment was performed at the University of Wisconsin in collaboration with Robert McDermott. ==== April 23 ==== Speaker: **Ramon Lopez, University of Texas, Arlington**; faculty host: **Heller** \\ Subject: **Space Weather** \\ **Abstract** \\ **Background**: http://www.uta.edu/ra/real/editprofile.php?pid=1926&onlyview=1 \\ Ramon E. Lopez received his B.S. in Physics in 1980 from the University of Illinois, and his M.S. and Ph.D. in Space Physics in 1984 and 1986, respectively, from Rice University. He is currently a Professor in the Department of Physics at the University of Texas at Arlington. Dr. Lopez is a Fellow of the American Physical Society and was awarded the 2002 Nicholson Medal for Humanitarian Service. His current research focuses on solar wind-magnetosphere coupling, magnetospheric storms and substorms, and space weather prediction. Dr. Lopez leads a research group that is working in both space physics and science education. Dr. Lopez is active in science education at a number of levels. Dr. Lopez has served as a consultant for a number of school districts around the country, as well as other organizations. He worked very closely with Montgomery County Public Schools (MCPS) in Maryland to help implement a hands-on science program in elementary and middle grades. He is the Co-Director for Diversity for the Center for Integrated Space weather Modeling (CISM), a Science and Technology Center funded by the National Science Foundation. In 2003, he was elected Vice Chair of the APS Forum on Education and served as Chair in 2005. Dr. Lopez has also served various education-related committees of the AGU (American Geophysical Union), and as a member of the Board of Directors of SACNAS. In the Fall of 2003, he was co-Organizner of the Introductory Calculus-Based Physics Course Conference, sponsored by the American Association of Physics Teachers. Dr. Lopez is also the co-author of a popular book on space weather entitled "Storms from the Sun", published by Joseph Henry Press, the tradebook arm of the National Academy Press. Space science seminar 1:00 p.m. - "The Current-Driven Magnetosphere" Convection in the ionosphere and magnetosphere is driven by solar wind energy, which powers the generation of a large-scale electric field that produces plasma motion. It is generally believed that there are two mechanisms by which solar wind energy generates convection: reconnection and a viscous interaction at the magnetopause. In this talk I propose that a third, fundamentally distinct mode of imposing convection on the magnetosphere and ionosphere exists. Current must flow across the bow shock as determined by the jump conditions, and the bow shock current represents a dynamo. The bow shock current closes in part through the ionosphere, which is a load. Thus it is possible to generate an ionospheric potential that is neither a product of reconnection nor of mechanical transport of energy across the magnetopause. The current-driven potential is imposed directly on the ionosphere by field-aligned currents that connect to the bow shock and which are driven by the mechanical energy extracted from the solar wind as it crosses the bow shock. Physics Education seminar Tuesday, April 22, 2008, 11:15 a.m. - "Visual representation in space and geoscience" Space science and geoscience are rich in visual representations of systems that are extends across large domains of space and time in 3-D systems. 3-D aspects can be represented by a varety of means, including perspective and color. These visual representations are generally created by subject matter experts who view the representations as self-evident, but novices may not have the same reaction, particularly when the perspective image is of something unfamiliar. Similarly, color scales are often used to represent information (such as temperature, height, time, flux, or other quantities) with the implicit assumption that red is a low value and blue is a high value. But students may not take that color scale as the major visual clue in the representation. In this talk I will review two studies made by our group that investigate student responses to visual representation of information. In one case the focus was on a 2-D representation of 3-D information through perspective drawing. In the other case the focus was on the use of color to represent a third dimension. We find that novices do not necessarily interpret these representations as intended by their creators. Department Colloquium - "Space Weather" As our technological civilization becomes more dependent of space technology, we become more vulnerable to changes in the space environment in which that technology functions. These environmental changes are known as “space weather.” In this talk I will discuss what drives space weather and how it affects human activities both in space and on the Earth. I will also discuss recent efforts by the Center for integrated Space Weather Modeling to create physics-based numerical simulations of the magnetosphere to be used in forecasting space weather. ==== April 30 ==== Speaker: **Kam-Biu Luk, University of California, Berkeley**; faculty host: **Heller** \\ Subject: **Reactor Experiments for Neutrino Oscillations** \\ **Abstract** \\ **Background**: http://physics.berkeley.edu/research/faculty/luk.html \\ There are compelling evidences for neutrino oscillation. Oscillations between three kinds of neutrino are completely described by three mixing angles, two mass-squared differences, and one CP-violating phase. CP violation in the lepton sector, if exists, might explain why there is more matter than anti-matter in the Universe. Yet whether the CP-violating effect can be studied with neutrinos or not is dictated by the last unknown mixing angle θ13. The primary goal of the Daya Bay experiment in China is to determine the value of θ13 by measuring the change in flux and the energy spectrum of the antineutrinos generated by the powerful Daya Bay nuclear power complex with three sets of detectors located underground at three different locations that are within 2 km from the reactors. ==== May 7 ==== Speaker: **G. J. Wasserburg, Cal Tech (geophysics)**; Faculty host: **Qian** \\ Subject: **Imagination, pulp fiction, science & exploration** \\ **Abstract** \\ **Background**: http://www.planetary.caltech.edu/faculty/wasserburg/ \\ **Isotopic Geochemistry and Cosmochemistry in the Lunatic Asylum** Professor Wasserburg and his colleagues in the "Lunatic Asylum" are carrying forward a vigorous research program in several areas. These range from theoretical studies to the development and application of analytical methods to the study of some natural systems. The research areas of interest are in cosmochemistry, geochemistry and aqueous geochemistry. The general purpose of the cosmochemical research is: 1) to understand the nucleosynthetic and chemical processes which led to the formation of dust grains around presolar stars; 2) to model early nucleosynthesis in galaxies; 3) to establish the chronology of events and processes which led to the formation of the solar system from the interstellar medium, using short and intermediate lifetime radioactive nuclides; 4) to understand the events during the early stages of solar system formation and the development and early evolution of planets. The geochemical studies are directed toward 1) the structure and evolution of large scale reservoirs within the earth and their relationship to major geodynamical processes and 2) the short term processes involving climate change, recent volcanism and fluid-rock interactions. The fluid rock interactions are particularly important with regard to environmental problems and the stability and storage of radioactive waste. Many of these geochemical studies directly involve field work. Wednesday, May 7th 2008 4:00 pm: Physics and Astronomy Colloquium in 131 Physics Speaker: G. J. Wasserburg, Cal Tech Subject: Imagination, pulp fiction, science & exploration This illustrated talk is directed toward both scientists and the general public. It will be on the interactions between imagination, the limits of imagination, speculation and some understanding of nature. Examples ranging from Leonardo da Vinci, through Jules Verne, the comic books, the Apollo landings on the Moon, and the astronomical exploration of the Universe. It is meant to stimulate thought on what really constitutes exploration and how popularization both stimulates and confuses real exploration. It may lead nations astray in wild "star wars" enterprises that are not really exploration. The talk will be leavened by humor and a variety of illustrations from "pulp fiction", and end in the mystery of quasars and dark matter. The latter will not be explained. ===== Old colloquiua ===== ^Date^Speaker (click name for more detail info)^Topics^Host (click name if you want to Email the host)^Participants^ |9/12|Juan Collar, Enrico Fermi Institute|Dark Matter Search, etc.|Pearl Sandick|Matt Fritts, Matt Strait, Jen Docktor, Tom Kelley, Perrie Cole, Abe DeBeneditti| |9/19|[[#september_19th|Nigel Cooper (Cambridge)]]|CM theory|[[levchenk@physics.umn.edu|Alex Levchenko]]| Yaroslav Lutsyshyn, Yen-Hsiang Lin, Matt Strait, Alexey Kobrinskii, Xi Chen, Matt Parker| |9/26|[[#september_26th|Susan Coppersmith (Wisconsin)]]|Quantum Computing|?| Jen Docktor, Yun Chen, Xi Chen, Abe DeBenedetti, Alexander Monin, Catherine Raach, Lee Wienkes, Bin Wu| |10/3|[[#october_3rd|Leo P. Kadanoff (U. Chicago)]]|Stellar Explosions|?| Farzad Sadjadi, Yaroslav Lutsyshyn, Xi Chen, Jun Chung, Susan Dorsher, Matt Strait, Tao Hu, Yves Adjallah,Lynn Wilson| |10/10|[[#october_10th|Bonnie Fleming (Yale)]]|Neutrino Oscillation|?|Matthew Strait, Alexander Monin, Maribel N'u~nezV, Susan Dorsher, Xinjie Qiu, Sujeewa Kumaratunga| |10/17|[[#october_17th|Ed Smith (JPL)]]|Space Physics|[[wilson@physics.umn.edu|Lynn Wilson]]| Scott Thaller,Lei Dai, Matt Strait| |10/24|?||?| participants here| |10/31|?||?| participants here| |11/7|[[#november_7th|Walter Gekelman (UCLA)]]|colliding plasmas|[[thaller@physics.umn.edu|Scott Taco Thaller]]| Lynn Wilson, Lei Dai, Matt Strait| |11/14|[[#november_14th|Earl Peterson, Keith Ruddick (UofM)]]|HEP|?| Farzad Sadjadi, Jin Chen, Matt Strait, Al Balmer,Shun Wang, Lynn Wilson| |11/28|Timothy Newman (Arizona)|biological physics|?|| |12/5|[[#december_5th|Tom Delworth (Geophysical Fluid Dynamics Lab)]]|Climate Modeling|?| Steve Snyder, Matt Strait| |12/12|[[#december_5th|Bob Pepin (UOM)]]|Stardusts Mission|?| Paul Barsic, Michael Milligan, Pearl Sandick, Abe DeBenedetti, Josh Ellis,Maribel NV| ==== September 19th ==== Speaker: **Nigel Cooper, Cambridge University**; faculty host, **Kamenev**\\ Subject: **Spinning Topological Phases out of Cold Atomic Gases**\\ **Abstract** - One of the most remarkable properties of a superfluid is its response to rotation. The formation of an array of quantized vortex lines is a dramatic manifestation of the macroscopic quantum nature of the superfluid. But what happens if one spins the superfluid so rapidly that the vortex lines become very closely spaced? I shall describe theoretical predictions of the appearance of novel and exotic phases in cold atomic gases at high vortex densities. These include topological phases exhibiting so-called "non-abelian" exchange statistics, with the potential to support universal topological quantum computation. ==== September 26th ==== Speaker: **Susan Coppersmith (Wisconsin – Chair)**; faculty host, **Dahlberg**\\ Subject: **Quantum computing: Opportunities and challenges**\\ **Abstract**: Quantum-mechanical phenomena such as quantum coherence, interference, nonlocality, and entanglement can be exploited to build new electronic devices and systems that differ fundamentally from current ones. Achieving these advances requires fundamental advances in a variety of disciplines as well as close interdisciplinary collaboration. This talk will discuss how close cooperation between researchers in different disciplines has enabled substantial new progress in the development of quantum dots in silicon/silicon-germanium heterostructures for quantum computing applications.\\ **Background**: http://uw.physics.wisc.edu/~coppersmith/ I am a theoretical condensed matter physicist working to understand the fundamental properties of a variety of systems that are far from thermal equilibrium. Current projects: http://uw.physics.wisc.edu/~coppersmith/vitae/current_projects_1_2007.htm ==== October 3rd ==== ===(Misel Lecture)=== Speaker: Leo P. Kadanoff (U. Chicago); faculty host, \\ Subject: **The Good, the Bad and the Awful - Scientific Simulation and Prediction**\\ **Abstract** - Worthwhile computer simulations are done to explore uncharted territory, resolve a well-posed scientific or technical question, or to make a design choice. Some excellent work is reviewed. Some less happy stories are recounted. I then concentrate my attention upon astrophysical simulations, showing how they can explore possible scenarios for stellar explosions.\\ **Background**: http://jfi.uchicago.edu/~leop/ Leo P. Kadanoff is a theoretical physicist and applied mathematician who has contributed widely to research in the properties of matter, the development of urban areas, statistical models of physical systems, and the development of chaos in simple mechanical and fluid systems. His best-known contribution was in the development of the concepts of "scale invariance" and "universality" as they are applied to phase transitions. More recently, he has been involved in the understanding of singularities in fluid flow. ==== October 10th ==== Speaker: **Bonnie Fleming (Yale)**; faculty host; **Cushman** \\ Subject: **Neutrino Oscillation**\\ **Background**- http://hepwww.physics.yale.edu/nup/ Our group, headed by Prof. Bonnie Fleming, studies neutrinos. We are largely an experimental group focusing on new physics in the neutrino sector. In the near term, we are working on the MiniBooNE experiment at Fermilab. In the long term, we are considering searches for CP Violation in the neutrino sector. Concurrently, we are doing R&D on the next generation of accelerator neutrino detectors -- Liquid Argon Time Projection Chambers. ==== October 17th ==== Speaker: **Ed Smith (JPL)**; faculty host, **Paul Kellogg**\\ Subject: **Space Physics**\\ **Background**: http://science.jpl.nasa.gov/people/ESmith/\\ • Experimental physics \\ • Measurement of magnetic and electric fields in space \\ • Heliospheric and Magnetospheric physics \\ • Description and properties of planetary magnetic fields and planetary interiors \\ • Solar modulation of galactic cosmic rays \\ • Hydromagnetic shocks, waves and discontinuities \\ • Properties of heliospheric and magnetospheric current sheets \\ • Origin of the solar-heliospheric magnetic field ==== November 7th ==== Speaker: **Walter Gekelman (UCLA)** ; faculty host, **Cattell**\\ Subject: **Three-dimensional current systems produced by colliding plasmas in a background Magnetoplasma**\\ **Abstract** - Results are presented from an experiment in which two plasmas, initially far denser than a background magnetoplasma, collide as they move across the magnetic field. The dense plasmas are formed when laser beams, nearly orthogonal to the background magnetic field strike two targets. The merging plasmas are observed to carry large diamagnetic currents. The interaction spawns the generation of intense waves in the plasma. The first burst of waves observed, are whistler waves and their dispersion and spatio-temporal structure will be presented. Less than a microsecond after the collision a "magnetic reconnection" event is triggered by the collision and the electric field induced in this event generates a field aligned current. This is the first step in the development of a fully three-dimensional current system. After several ion gyro-periods the current systems become those of shear Alfven waves. As local currents move, small reconnection "flares" occur at many locations throughout the plasma volume. Magnetic field lines associated with these waves are shown in the figure above. The data clearly show that the induced electric field is carried though the system by shear Alfven waves. The relation of this experiment to phenomena in space and astrophysics will be discussed. \\ **Background**: http://plasma.physics.ucla.edu/bapsf/pages/research.html The upgraded LAPD is the centerpiece of the Basic Plasma Science User Facility. It is a significant enhancement of the Large Plasma Device (LAPD) at UCLA. The machine occupies an entire floor in the new Science and Technology Building (completed in May of 1998), a modern research facility with high electrical power handling capabilities (30 MW). Present, ongoing activities in LAPD are sponsored by ONR, DOE, and NSF. ==== November 14th ==== Speaker: **Prof. Earl Peterson and Prof.Keith Ruddick**\\ Subject: History of High Energy Physics at Minnesota ==== November 28th ==== Speaker: **Richard Ellis (Caltech)**; faculty host, **Hanany**\\ Subject: **The Case for a Significant Population of Sub-Luminous Star Forming Galaxies at Redshift 10**\\ **Abstract**: Locating and characterizing the sources responsible for cosmic reionization and ending the so-called "Dark Ages" is a new frontier in theoretical and observational astronomy. A popular view is that, a few hundred million years after the Big Bang, a high density of low mass star forming galaxies were produced. Finding and studying such faint sources is a major driver for future facilities such as the James Webb Space Telescope and the proposed Thiry Meter Telescope. Meanwhile, by harnessing the strong gravitational lensing power of massive clusters, the first candidate sources beyond z=7 are being found and studied. I will describe the progress (and limitations) of the work we are doing with Keck, Spitzer and Hubble in this area which provides a first tentative glimpse of the Universe at redshift 10.\\ **Background**: http://www.astro.caltech.edu/~rse/ I am working primarily in observational cosmology addressing issues related to the nature of the world model, the origin and evolution of galaxies, the growth of large scale structure and the nature and distribution of dark matter. I am enthusiastic about the use of new instruments and observational opportunities when they further the progress that can be made in these areas. ==== December 5th ==== Speaker: **Tom Delworth**; faculty host; **Cushman**\\ Subject: **Climate Modeling**\\ **Background**: http://www.gfdl.noaa.gov/~td/ I am a research scientist in the Climate Dynamics and Prediction Group of the Geophysical Fluid Dynamics Laboratory My primary research interests are (a) decadal to centennial scale climate variability and change, including anthropogenic climate change, and (b) the role of the ocean in climate. Most of my work involves the use of climate models in concert with observational data. ==== December 12th ==== Speaker: **Bob Pepin, U of M**\\ Subject: **Stardust Mission**\\ **Background**: Origin and early history of volatile elements and compounds in the solar system as revealed by mass spectrometer measurements of noble gases and nitrogen in meteorites and lunar samples. Areas of particular interest include the composition of the primordial solar nebula, isotopic signatures of nucleosynthesis in primitive meteorites, the compositional history of solar wind and flares over the past 4+ billion years, and the origin and evolution of volatiles in the interiors and atmospheres of Earth, Mars and Venus.