2004 Seminars
FRIDAY 3 December 2004
11 am - Room 701
Brian Warner
Department of Astronomy, University of Cape Town, SA
Rapid Oscillations in Cataclysmic Variable Stars and X-Ray Binaries.
Among the many exotic objects in the sky there are binary stars in which a compact star is accreting mass from its companion. Those in which the accretor is a white dwarf are known as cataclysmic variables (CVs - and novae are members of this class), and those in which the accretor is a neutron star or black hole are known as X-Ray binaries. Many of them show rapid quasi-periodic oscillations of brightness - on time scales of 1 - 1000 secs for the CVs and 1 - 100 millisecs for XRBs.
The lecture will display some of the rich phenomenology of these oscillations and report on recent observations of CVs which show close similarities to those of XRBs. One result calls into question the need for a General Relativistic explanation of the harmonics seen in some black hole XRBs.
FRIDAY 19 November 2004
11 am - Room 701
Richard Gray
University of Auckland
Diamond Detectors in the Compact Muon Solenoid
The CERN Large Hadron Collider (LHC) will collide two counter rotating proton beams. The energy stored in each beam is about 350MJ. Beam losses due to an accelerator failure could cause damage not only to the machine but also to the experiments. Within the Compact Muon Solenoid experiment (CMS), a Beam Condition Monitor (BCM) is foreseen, to monitor fast increments of the flux near the interaction point, to flag the onset of adverse beam conditions within the CMS experiment, and if necessary, to input into the beam abort system of the LHC. Strong constraints on BCM design from radiation hardness, a minimal material and services budget, and the need for fast signals from sensors with high sensitivity and a large dynamic range, have led to the investigation of synthetic chemical vapour deposited (CVD) diamond for the BCM sensor.
TUESDAY 9 November 2004
12 noon - Room 701
Donald C O’Shea
Georgia Institute of Technology, School of Physics
Atlanta, GA
Publishing Optics
The publication of the results of our research is the final step in our scientific effort. The distribution of a researcher's findings though a scientific journal began on February 16, 1672 in the Philosophical Transactions of the Royal Society of London. Until recently the way we publish our work has changed little. As Editor of Optical Engineering, I will describe the procedures that we currently use to publish papers in this digital electronics era. As we move from print publications to their electronic versions we are gaining flexibility, but we also creating certain problems. Concepts such as real-time publishing and virtual journals are being to be introduced and problems as old as plagiarism and new as open access journals must be addressed.
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Donald C. O'Shea’s current research interest is the application of optical engineering to ultrafast pulse devices. He is the co-inventor of a display system for low vision patients and has published more than 50 scientific publications and presented a similar number at national and international scientific meetings.
FRIDAY 5 November 2004
11 am - Room 701
Dawn McMillan
Manager
Physical Sciences Library & Engineering Library, UC
Update 2004 – What’s New in Your Library
Physical Sciences Library staff will provide an introduction to the library's people, resources and services, highlighting recent changes and library news relevant to the department. Particular focus will be given to information literacy and how the library, in conjunction with the academic department, can help students to make best use of the resources available to support their learning. There will also be brief discussion of some tools for keeping current, changes to electronic journal management and some discussion on library collection issues for the Department. The session will conclude with a question and answer session and hopefully some one-on-one between library staff and the faculty staff and research students.
FRIDAY 29 October 2004
11 am - Room 701
Suruj Seunarine & Kahae Han
Department of Physics & Astronomy
Neutrino Astrophysics at the University of Canterbury
Currently there are two types of neutrino astrophysics experiments being carried out at the South Pole. The University of Canterbury has researchers involved in both of these experiments. IceCube in particular will be a cubic kilometre array of optical detectors buried below the Antarctic ice. We recently joined this experiment and we have been actively participating in simulation studies. The primary signal for IceCube is a muon neutrino scattering off a nucleon in the ice to produce a muon. The muon emits optical Cerenkov radiation which will be detected by IceCube. However IceCube will also detect electron neutrinos through cascades. Our group has done studies on the light yield form cascades and has also done a study on the possible long range muon background from hadronic cascades. We will present an introduction to the IceCube experiment and discuss our contribution to the project.
FRIDAY 22 October 2004
11 am - Room 701
Departmental Conference: The return
Mohammed Habdan
Dosimeters Using Plastic scintillators and Fibre Optics
In-vivo radiation dose measurement is a significant treatment quality assurance process. In this process the accuracy of dose delivered is verified, provide information on beam location and check that radiation is not delivered to nearby healthy tissue. The requirements for a useful dosimeter include: very small size, being tissue equivalent, has fast response, has linear response with dose and relatively inexpensive. The small size is needed to assess local doses, prevent exposing sensitive tissue peripheral to radiation beam. If small enough it may be possible to insert one or more dosimeter inside the human body. In a tissue equivalent dosimeter, the response per unit dose would be independent of radiation energy and calibration repetitions will not be necessary when the spectrum of incident radiation has changed. The proposed dosimeter consists of tissue equivalent plastic scintillator mounted on fibre optics. When exposed to radiation, visible scintillation light (˜425nm) is produced, and transmitted through fibre optics to a photodiode. The photodiode converts light into electrical signal; the current produced is proportional to the dose rate. The total produced charge will be proportional to the total dose received.
René Reichel
A UHV Compatible Cluster Deposition System
The design and operation of a new UHV-compatible atomic cluster deposition system is described. The design is optimised for high cluster fluxes and for the production of cluster-assembled nano-devices. One key feature of the system is a high degree of flexibility, including interchangeable sputtering and inert gas aggregation sources, and two kinds of mass spectrometer, which allow both characterisation of the cluster size distribution and deposition of mass-selected clusters. Another key feature is that clusters are deposited onto electrically contacted lithographically defined devices mounted on an UHV-compatible cryostat cold finger, allowing deposition at room temperature as well as cryogenic and elevated temperatures. In-situ electrical characterisation of cluster-assembled devices can then be performed in the temperature range 1.2 K to 475 K.
Karla Kincaid
CERN Summer School
I had the unique opportunity to attend the CERN Summer School. CERN is 15 minutes outside of Geneva, Switzerland, on the border between Switzerland and France. CERN is currently building the Large Hadron Collider (LHC) so by CERN standards it is quiet here without the accelerator running. They are presently installing the first magnets which are 60 meters long and must be lowered horizontally into the tunnel. The magnets each weigh 33 tons and are transported on a train in the 27km tunnel to their locations where robots must position them to within 1/10 of a millimetre precision. I also had the opportunity to work on the MEDIPIX Project. I was given the task of measuring the spectrum of an x-ray beam along the longitudinal axis of the MEDIPIX chip. The x-ray beam is collimated and directed at the side of a high resistivity Si sensor. Using the pixel segmentation in depth and its thresholding and counting capability it should be possible to study charge deposition and collection and compare the results with theoretical calculations.
Ben Leith will also be giving a presentation.
FRIDAY 15 October 2004
11 am - Room 701
Prof Eberhard Grüen
Erskine Visitor
Max-Planck-Institut für Kernphysik
Dust in Interplanetary Space
The solar system is a natural laboratory, accessible by a variety of methods, for studying the astrophysics of dust. Various types of dust have been identified in interplanetary space. Close to Jupiter intense streams of nanometer-sized ash particles emitted from the volcanoes of Jupiter’s moon Io have been observed. Concentrations of collisional debris in the asteroid belt have been identified by infrared observations. Comets shed large amounts of dust into the inner planetary system. Interstellar grains passing through the planetary system have been identified by in-situ dust instruments and are recorded as radar meteors. These dust populations are the target of future dust observatory missions in space.
FRIDAY 8 October 2004
11 am - Room 701
Prof Chris Sneden
Erskine Visitor
Department of Astronomy, University of Texas
It’s a Blast!
Evidence for Rapid Neutron-Capture Nucleosynthesis in the Early Galaxy
All of the elements of the Periodic Table beyond the iron peak are synthesized principally in neutron bombardment reactions. The abundance distributions of these elements in metal-poor halo stars offer unique ways to gain insight into very early Galactic nucleosynthesis. I will discuss recent high resolution spectroscopic studies of the lowest metallicity stars, which have revealed three main features of their neutron-capture element contents. First, extremely large star-to-star scatter is observed in the overall bulk levels of the neutron-capture elements compared to the iron-peak elements. This is direct evidence of the effects of individual nucleosynthesis events that occurred in our newly formed Galaxy. Second, detailed abundance ratios among the neutron-capture elements are very different than their solar-system values, clearly pointing to the dominance of rapid neutron-capture nucleosynthesis that accompanied the deaths of the first short-lived high mass halo stars. Finally, thorium is now being routinely detected in low metallicity stars. In at least two stars, uranium also has been discovered. I will highlight the prospects and perils of application of these elemental abundances to estimates of the Galactic chronometric age.
FRIDAY 1 October 2004
11 am - Room 701
Alan Gilmore
Mt John University Observatory
Department of Physics and Astronomy
The MOA Telescope & Other Developments at Mt John
Work on the MOA Telescope building proceeds apace at Mt John. The telescope itself arrives from Kyoto in early October, with completion expected later in the month. The large-format CCD camera, with lenses made at IRL in Lower Hutt, will be installed soon after. This talk describes the project and, if time allows, some of the other work at Mt John.
FRIDAY 24 September 2004
11 am - Room 701
Chris Glasbey
Head of Research
Biomathematics and Statistics Scotland
A statistical approach to image warping
Image warping is a transformation which maps all positions in one image plane to positions in a second plane. It arises in many image analysis problems, whether in order to remove optical distortions introduced by a camera or a particular viewing perspective, to register an image with a map or template, or to align two or more images. The choice of warp is a compromise between a smooth distortion and one which achieves a good match, and it can be formulated statistically, as maximum penalised likelihood (Glasbey and Mardia, 2001). The likelihood measures the similarity or match between images after warping and the penalty is a measure of distortion of a warping. We identify null-set distortion criteria, with each criterion uniquely minimised by a particular set of polynomial functions, and we construct matching criteria in the Fourier domain. Typically, high-frequency terms are dominated by noise, and we use a Fourier-von Mises image model, in which phase differences between Fourier-transformed images having von Mises distributions. The method is motivated by, and used to solve, two applied problems: to align microscope images obtained using different optics, and to discriminate between species of fish from photographic images.
Glasbey, C.A. and Mardia, K.V. (2001). A penalized likelihood approach to image warping (with discussion). Journal of the Royal Statistical Society, Series B, 63, 465-514.
FRIDAY 17 September 2004
11 am - Room 701
Richard D Tilley
School of Chemical and Physical Sciences
Victoria University of Wellington
The McDiarmid Institute of Advanced Materials and Nanotechnology Liquid phase synthesis and applications of Si and FePt nanoparticles
There is a great deal of current research involving nanoparticles because of their interesting properties and potential for many applications. The discussion will focus on the liquid phase synthesis of nanoparticles and two of the most promising areas of nanoparticle research; the use of luminescent silicon particles for future LEDs and biological imaging agents magnetic and FePt nanoparticles for the next generation of hard disk storage media.
TUESDAY 14 September 2004
12 noon – S4 lecture theatre
Kent Cullers
Director, SETI R&R
SETI Institute
Extending the Senses
The natural intent of experimental physics is to extend the senses into new realms. The remarkable synthesis of the 21st century is the unification of enabling technologies and new scientific technologies.
SETI, the radio search for extraterrestrial intelligence, searches the heavens for signs of technology. Our civilization modifies the electromagnetic spectrum of the solar system, creating bright microwave lines that outshine our sun by a factor of a million. This makes our technology detectable to any alien civilization that is sufficiently advanced.
New receiving antennas that can also be used as beamed transmitters may soon make our civilization even more visible. The SETI Institute is currently designing such antennas as well as new generations of computers. The expectation is that radio searches will expand rapidly, because they are based on the explosion in computer technology.
Come listen to the sounds of the cosmos and learn how computers analyze data to differentiate the traces of technology from natural signals in the sky.
FRIDAY 10 September 2004
11 am - Room 701
SQNLDR Jim Rankin
RNZAF
PHYSICS IN ACTION – Applied Classical Mechanics
The seminar will discuss the physics involved in an aircraft in a 'spin'. A spin results from an aircraft departing controlled flight after stalling. A steady spin is the result of a balance of aerodynamic, inertial and gyroscopic forces. A surprisingly small change in aircraft mass or weight distribution can make the spin characteristics markedly change, and even result in the spin being irrecoverable - as happened to an RNZAF Strikemaster aircraft which crashed some years ago.
FRIDAY 3 September 2004
11 am - Room 701
Dr Gary Bold
Department of Physics, University of Auckland
Long-range Underwater Acoustics
Low-frequency sound is the only tool we have for probing ocean structure, as frequencies below 100 Hz can travel large (megametre) distances with little attenuation, trapped in a focussing channel. However, high ambient noise levels and the relatively low power of man-made sources mean that sophisticated pulse-compression techniques are necessary to enhance the received signal-to-noise ratio.
FRIDAY 27 August 2004
11 am - Room MSCS 031
Mathematics Building Basement
In conjunction with Kerr Fest.
Prof. Andy Fabian
Institute of Astronomy, University of Cambridge
Effects of strong gravity on X-ray spectra observational evidence for Kerr black holes.
The X-ray spectra of accreting black holes, both in active galactic nuclei and stellar mass sources, often show a broad skewed iron emission line. The red wing of the line is predominantly due to gravitational redshift and in some cases indicates that the emission originates from only 2 - 3 gravitational radii. Large light bending effects at such small radii affect the variability in a manner consistent with observation. The data provide strong evidence for rapidly spinning, Kerr, black holes. Recent data and future prospects will also be discussed.
Biographical:
Andy Fabian is a Royal Society Research Professor at the University of Cambridge, and head of its X-ray astronomy group. He obtained his Ph.D.
at the University of London in 1972, moving to the Institute of Astronomy in Cambridge in 1973 and taking up his current post there in 1982.
He is Vice Master of Darwin College Cambridge, a Fellow of the Royal Society and is a member of NASA's Chandra satellite project. He was awarded the Bruno Rossi Prize of the American Astronomical Society in 2001 jointly with Y. Tanaka.
He has broad interests in X-ray astronomy, having worked on data from most orbiting X-ray satellites. Currently his main interests are in clusters of galaxies and accreting black holes, both in active galaxies and Galactic ones. He has co-authored more than 500 research papers in refereed journals.
FRIDAY 20 August 2004
11 am - Room 701
DR JOHN CHRISTIE
Lincoln Ventures Ltd
The Electrical Properties of Hydrophilic Solids.
Water is absorbed in varying degrees by most organic solids and has dramatic effects on their low frequency electrical properties. The electrical response shows remarkable similarities which are independent of the physical and chemical characteristics of the absorbent and despite being the subject of study since 1928, a comprehensive understanding still eludes researchers. Drawing on a detailed review of the (very extensive) literature and recent measurements on cellophane, I present a new model which can explain all of the main electrical characteristics.
In this model conduction is predominately due to protons hopping between absorbed water molecules. The conductivity is determined by a certain critical distance proportional (but not equal) to the average distance between the water molecules and it is this factor which explains the dependence of conductivity on water concentration. The striking dielectric characteristic, including relative permittivities as high as 109, can be explained by the accumulation of mobile charge densities many orders of magnitude greater than can occur in rotating dipole systems. The model also explains the frequency dependence of the electrical properties, and makes the interesting prediction that electrical properties, including permittivity, will be dependent on macroscopic sample dimensions.
FRIDAY 13 August 2004
11 am - Room 701
Associate Professor Ewan Stewart
Department of Physics at KAIST, South Korea
Life, the Universe, and the Theory of Everything
I will discuss anthropic selection, eternal inflation, the accelerating universe, and the structure of the theory of everything.
FRIDAY 6 August 2004
11 am - Room 701
Professor Jacob Katriel
Department of Chemistry
Technion - Israel Institute of Technology Haifa 32000, Israel
The symmetric group: the class-algebra point of view
The conjugacy class-sums (CSS's) of the symmetric group commute with all the group elements, and their common eigenstates span the corresponding irreducible representations. Combinatorial algorithms for the CCS algebra and for the eigenvalues of the CCS's will be presented, and asymptotic properties of their spectra, that suggest an equipartition principle, will be discussed. Two generalizations - the Hecke algebra and the braid group - will be briefly introduced.
FRIDAY 23 July 2004
11 am - Room 701
Professor Michael Bessell
Research School of Astronomy & Astrophysics (RSAA)
Australian National University
Canberra, Australia
Timescales of Star and Planetary Formation
Mike Bessell has a wide interest in astrophysical problems and leads the Instrument Group at RSAA. Mike was a Visiting Erskine Fellow to this Department in 1994.
FRIDAY 16 July 2004
11 am - Room 701
William Joyce
Department of Physics & Astronomy
The Legacy of Feynman
Feynman once thought “wouldn’t it be funny if all these strange [Feynman] diagrams become common place in physics” or so the tale goes. In fact such diagrams seem to play an every increasing role in many disciplines. Diagrams or pictures do capture our imagination, perhaps because a picture provides a parallel feed of information and must be the fastest way to assemble information in our brain? Whatever the reason, they enrich our understanding and aid in calculation. The aim of this talk is to give a survey of such things and reveal the underlying structure common to all.
MONDAY 12 July 2004
12:00 noon - Room 701
Mark Kruse
Duke University, USA
Recent results and prospects from the CDF experiment at Fermilab
We are entering a fascinating next few years in High Energy Particle physics, with high expectations for significant insights to some of our most fundamental questions. In particular, we expect to gain crucial understanding of the question as to how mass is generated in the universe.
Currently the highest energy collider in the world is the Tevatron at Fermilab in the US, where data is now being collected and analysed.
In 2008 the Large Hadron Collider(LHC) at CERN in Europe will turn on at 7 times the energy of the Tevatron, to take over where the Tevatron leaves off.
After an introduction to High Energy Physics(HEP), the questions we are trying to answer, and the experiments designed to answer these questions, I will discuss the latest results from the CDF experiment at Fermilab. There is much anticipation from results involving the top quark and searches for the Higgs boson, and I will concentrate on these topics and their prospects in the coming years before the LHC comes on line.
FRIDAY 11 June 2004
11 am - Room 701
Professor Rob Goldblatt
School of Mathematics and Computer Sciences,
Victoria University of Wellington
What is a Topos?
A CATEGORY can be thought of as the entire "universe" of a branch of mathematics. Category theory was originally devised to provide a language for explaining the relationship between Algebra and Topology but has now become important in other parts of mathematics, and is used in other areas such Computer Science and Theoretical Physics, as well as becoming a subject in its own right.
A topos is a special kind of category that links together the worlds of Topology, Set Theory and Algebraic Geometry.Each topos has its own version of the laws of logical reasoning, which may differ from the standard laws of Boolean logic.
This talk will provide an introduction to these ideas for the non-specialist.
FRIDAY 4 June 2004
11 am - Room 701
TREVOR CAREY-SMITH
Department of Physics & Astronomy
The Canterbury University ST Radar: investigations into stratosphere-troposphere dynamics.
The VHF stratosphere-troposphere radar is a very important tool in the study of atmospheric dynamics, particularly when data with a high temporal and/or height resolution is necessary. Processes such as frontal passages, tropopause folds and atmospheric gravity wave/mountain wave activity can be observed in great detail using an ST radar.
In this talk I will discuss the principles behind the operation of ST radars and in particular the design details of the Canterbury University radar. The first phase in the development of this radar is completed and it has been operational for nearly two years, measuring vertical wind speed and providing information about the structure of the troposphere and lower stratosphere.
The talk will also cover some recent research on the effect of wind direction on mountain wave activity. Using data from a RAMS model (provided by NIWA) a relation is made between the altitude and direction of the wind and the magnitude of mountain wave activity.
FRIDAY 21 May 2004
11 am - Room 701
Greg Bodeker
NIWA
Climate Change – who did it, who is likely to do it in the future?
Over the past 250 years, anthropogenic emissions of a number of gases, primarily CO2, CH4 and N2O, have led to considerable increases in their concentrations in the Earth's atmosphere. Because these are greenhouse gases (GHGs) they have led to increases in radiative forcing and ultimately to increases in global mean surface temperature. The purpose of this talk is to examine the relative contribution of 4 different country groups to climate change to date, and how these proportions may change in the future (based on a number of potential emission scenarios developed by the Intergovernmental Panel on Climate Change). The country groups considered are:
- OECD90: comprising Canada, USA, OECD Europe, Oceania and Japan.
- REF: comprising Eastern Europe and the Former Soviet States
- ASIA: comprising the India region, the China region, and Southeast Asia
- ALM: comprising Latin America, Africa, and the Middle East
A simple climate assessment model has been developed to track the 'cause and effect chain' from changes in emissions to changes in concentrations to changes in radiative forcing to changes in global mean surface temperature to changes in sea-level rise. The key components of this model and the results from the calculations tracking the cause and effect chain will be presented. Furthermore, the model will be used to assess the contribution of each of the country groups listed above to the modelled changes. The problems associated with such attribution of change in the presence of non-linear processes will also be discussed. Model results will be compared with available measurements and some general discussion of key climate change issues will be presented.
This research follows a proposal by Brazil during the Kyoto Protocol negotiations to link the relative contributions of Annex I Parties (primarily developed countries) to emission reductions with the relative contributions of Parties to the global mean surface temperature increase.
Tuesday 18 May 2004
12 pm - Room 701
Richard P Hugtenburg
Anomalous elastic photon scattering in dilute aqueous ions
Direct measurements of the cross-sections for elastically scattering photons in the vicinity of atomic orbital edges are of interest because of the potential to yield atom-specific electronic configurations similar to X-ray absorption fine-structure (XAFS) in a small-angle scatter imaging mode. Recent studies of metal uptake in breast tumours support the usage of a modality that would distinguish nutrient metal ions from those contained in tissue remodelling metalloproteins such as the Zn bearing MMP-2. Direct measurement of cross-sections has been attempted using several techniques but little data exist for energies near atomic orbital edges. The high energy resolution and tuneability of synchrotron sources has been exploited to obtain cross-sections from a number of systems but competing processes such as absorption and Compton scattering mean that the results most consistent with theory have only been obtained in gas-cells. The measurement of dilute concentrations of ions in aqueous and glassy systems has been explored in which case scattering in the medium is well characterised as it occurs far from atomic orbitals, the measurement is preformed at high angles so as to be free from the effects of diffraction. Conventionally anomalous scattering is used to resolve questions of phase in macromolecules but the method normally relies on the utilisation of the dispersion relations which enable the determination of scatter cross-sections from absorption measurements. The dispersion relations are however only accurate at low-angles. For higher angles theoretical cross-sections are obtained from computationally intensive S-matrix calculations.
FRIDAY 28 May 2004
11 am - Room 701
Geoffrey Stedman
Department of Physics & Astronomy
TRY CROSSING YOUR FIELDS
I will discuss a number of topics in physics where it is useful to cross electric and magnetic fields: just one belongs directly to the ring laser project, Lieth Copper's thoughts on axion detection; another is the issue of Jones birefringence which we brought in from the cold about 10 years ago thanks in part to our understanding of time reversal invariance and associated selection rules in quantum theory for nonlinear optics - Jones birefringence has since been detected experimentally. This gives me an opportunity to speak of some work that has not been presented to the department previously, done in collaboration with Norwich University.
I will also mention some ill known properties of Maxwell theory to do with Poynting's vector and momentum conservation, which I have mentioned in seminars, but many years ago; other such topics may also be included.
FRIDAY 7 May 2004
11 am - Room 701
Richard Dowden
Emeritus Professor, University of Otago
The World-Wide Lightning Location Network (WWLLN) using VLF
At around 10 kHz, near the maximum spectral density of lightning emission, the attenuation in the earth-ionosphere waveguide is low enough to allow very strong lightning strokes to be detected on the other side of the world. Precise measurement of the time of the group arrival (TOGA) of the impulse (“sferic”) of a single stroke at a minimum of four sites allows location of the lightning stroke to within 3-6 km, depending on where it occurs in the world. The precision timing is provided by GPS (to within ~ 100 ns) and the stroke locations are available by Internet to anywhere within ~ 10 s of the stoke happening.
After an outline of the principles involved, a continuously looped “movie” of a full day (26 Feb 2004) of WWLL will be shown. With a speed-up factor of 3000, each cycle of the 24-hour loop takes about 30 seconds enabling explanation of several diurnal features in repeated cycles.
We currently have 20 sensors logging sferic activity in the VLF band.
FRIDAY 30 April 2004
11 am - Room 701
Derek Boyd
University of Maryland, USA
A Burning Plasma: The Next Step in Experimental Fusion Physics.
Over the past half century there has been considerable progress in the physics of hot plasmas laying the foundation for constructing an energy producing reactor based on fusion reactions of light nuclei. This development rivals that achieved in computing power over the same period. There is now a global consensus that the next experimental step should be to construct a machine for the study of burning plasmas.
This talk will describe what is meant by the term “burning plasma” by looking at the power flows both into and out of the reacting plasma. Then the differences between a burning plasma and those studied to date will be listed and what unexplored physics regimes will become accessible in the burning plasma.
Finally the current status of international attempts to build a burning plasma device called ITER at a cost of five billion US dollars will be presented.
FRIDAY 26 March 2004
11 am - Room 701
R A Cowley
University of Oxford
Do Phase Transitions have One length Scale?
The scaling theory of phase transitions developed by Fisher, Halperin, Hohenberg and Stanley has been very successful at explaining a large number of experimental results and is generally considered to be in agreement with the observations. Nevertheless, the length scale has not been measured in many cases apart from some low resolution measurements made with neutron scattering techniques. High resolution x-ray scattering techniques have enabled the measurements to be extended to long distances, of order 10000Å, and closer to the phase transition where the scaling theories are expected to be more successful. The results of all the high resolution measurements show the existence of two different length scales in contradiction with theory. Various explanations for this discrepancy will be discussed.
FRIDAY 19 March 2004
11 am - Room 701
Scot A C Gould
W M Keck Science Center, The Claremont Colleges, Claremont, California
Silk Stalkings: A multi-disciplinary approach to understanding the use of silk in prey capture.
The silk from spiders, particularly the major ampullate silk, possesses an exceptional combination of tensile strength and elasticity, which gives the web structure and strength to facilitate the capture of prey. This talk will discuss how scientists are using a multi-disciplinary approach, from the use of amino-acid sequencing to stress-strain measurements to computer modeling, to understand the structure of silk and how the spider uses silk for prey capture.
Professor Gould is a physicist who has been involved in the development of the atomic force microscope (AFM) since its inception. He has published on numerous applications of the AFM including the imaging of zeolites, synthetic polymers, natural polymers, amino-acid crystals, cells and other important biological elements. He is visiting U. of Otago during a sabbatical from his home college so that he can revisit some cool work involving Black Widow spiders.
THURSDAY 18 March 2004
11 am - Room 701
Richard Packard
Department of Physics, University of California, Berkeley
Superfluid 3He Josephson weak links: a new quantum gyroscope
Arrays of sub-micron apertures connecting two reservoirs of superfluid 3He exhibit properties characteristic of Josephson weak links. This lecture will describe several recent experiments demonstrating various superfluid Josephson effects including: quantum oscillations, the Shapiro effect, and pendulum motion. I will describe how we directly measure the current-phase relation and the unexpected physics that was discovered. Superconducting weak links can be configured into a two path quantum interferometer, the dc SQUID. We have developed an analogous device using superfluid 3He. Whereas the superconducting SQUID is a sensitive detector of magnetism, the superfluid device is a sensitive detector of rotation. I will describe recent experiments with a prototype superfluid dc-SQUID and discuss the possible limiting sensitivity of this technology.
1. Superfluid Josephson weak links, J.C. Davis and R.E. Packard, Rev. of Mod. Physics, 74, 741 (2002)
FRIDAY 12 March 2004
11 am - Room 701
Klaas de Boer
University of Bonn, Germany
The Milky Way Halo and Infalling Gas Clouds
The disk of our Milky Way is embedded in a roughly spherical region called the Milky Way Halo. In it one finds stars, generally thought to be old, as well as the globular star clusters, known to be old. That vast space is filled with presumably hot gas but there are clouds of neutral gas as well. These neutral clouds move predominantly towards the Milky Way disk at considerable speed and are hence called the infalling halo high-velocity clouds.
Several proposals exist for their origin. They range from clouds returning in a galactic fountain-like flow, clouds torn from dwarf galaxies being accreted, to clouds falling in from extragalactic space. Also the mass lost by red giant stars in the halo contributes to this mass flow. The size of its contribution is derived.
FRIDAY 5 March 2004
11 am - Room 701
Hugo Levato
The Argentina National Facility for Ground-Based Astronomical Observations
Dr. Levato will review the characteristics of the site and some of the instruments. He will discuss the observations that they provide and the opportunities for cooperation. Finally, Dr. Levato will briefly mention some of the research programs that are being carried out at the site.
FRIDAY 27 February 2004
11 am - Room 701
Manfred Simon
University of Siegen, Germany
PAMELA: A Satellite Experiment for Direct Measurements of Energetic Cosmic Matter and Antimatter from Space
PAMELA is a new international satellite experiment which will be launched in the year 2004. It is designed to measure with an unprecedented precision the energy spectra of protons, antiprotons, electrons, positrons and of light elements up to some hundred GeVs. It will also be able to look for Anti Helium down to a level of 10-8. These observations have strong links to particle physics, astrophysics and cosmology. They are connected to Dark Matter search and to propagation aspects of these particles in the interstellar medium. The talk will describe the PAMELA experiment in context to cosmic ray research in general, will illustrate the experimental approach and will discuss the scientific objectives.
FRIDAY 20 February 2004
11 am - Room 701
Robin Tucker
University of Lancaster
Gravity and Sagnac Revisited
Certain gravitational fields show a remarkable resemblance to those that satisfy Maxwell's equations for electromagnetism. Furthermore their interaction with matter is analogous to that in electrodynamics. However this analogy is not perfect. A survey of gravito-electro-magnetism will be given in the context of "gauge theory" and experimental efforts to detect the gravito-magnetic Faraday effect using Sagnac technology.
THURSDAY 19 February 2004
11 am - Room 701
John Garth
Alberquerque, New Mexico
Retired from Air Force Research Laboratory
Electron/photon transport – key to radiation physics? A review.
The theory of electron/photon transport may be considered as the unifying theory for major portions of radiation physics. In this talk, I will briefly survey the wide range of topics and application areas that involve the transport of electrons and x-rays (as well as positrons) through matter. I will also mention how certain applications trigger further model development, so that higher accuracy and speed can be achieved. Perhaps the most active application area utilizing electron/photon transport is the medical field of radiation therapy.
This talk is actually an introduction to a book I am writing - as a physicist to physicists (as well as others) - to demonstrate that radiation physics (for electrons and photons) deserves consideration as an active area for basic physics research, has surprising unity as well as complexity, is extremely rich in applications and shows beautifully the interplay of theory and experiment. At the end of the talk, I will point out fruitful areas for further basic research.
FRIDAY 13 February 2004
11 am – Room 701 Rutherford Building
Louis Lyons
Department of Particle & Nuclear Physics
University of Oxford, UK
Bayes versus Frequentism: the return of an old controversy
It is possible to spend a lifetime analysing data without realising that there are these two very contrasting approaches to the subject.
This talk explains the differences, and gives examples from physics and from everyday life to illustrate situations where they yield different answers.
FRIDAY 23 January 2004
11 am- Room Room 701
Mirian Tsulaia
INFN, Padova, Italy
On Higher Spins and Tensionless Limit of String Theory
We discuss string spectra in the low-tension limit using the BRST formalism, with emphasis on the role of triplets of totally symmetric tensors and spinor-tensors and their generalizations to cases with mixed symmetry and to (A)dS backgrounds. We also present simple compensator forms of the field equations for individual higher-spin gauge fields that display the {unconstrained} gauge symmetry of a previous non-local construction and reduce upon partial gauge fixing to the (Fang-Fronsda)l equations. For Bose fields we also show how a local Lagrangian formulation with {unconstrained} gauge symmetry is determined by a previous BRST construction.