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2007 Seminars
Monday 10 December, (Extra Seminar)
Professor James E. Morris Department of Electrical & Computer Engineering, Portland State University, Portland.Nanoparticles for Nanoelectronics Traditional conduction models for metal island films on insulating substrates are based on electrostatically activated tunnelling, but under-estimate actual conductances by orders of magnitude. A modified model has made significant headway with this problem, as demonstrated by simulations. The simplest discontinuous “film” is the single island Coulomb Block, which forms the basis of the single-electron transistor (SET). Room temperature SETs employ chains of islands, i.e. 1-D discontinuous films. The conventional numerical SET model is extended by application of the discontinuous thin film (DTF) work. Practical applications of discontinuous films are impeded by the difficulty of fabricating reproducible, stable structures, particularly for low TCR films which are the most susceptible to drift. Similar difficulties are experienced with SET islands, and a technique to manufacture stable and reproducible DTFs and SETs is described.
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Friday 7 December 2007
Geoff E Stedman Emeritus Professor,
Department of Physics, University of Canterbury
QED for atoms
Is has suddenly become fashionable recently to apply the full diagram formalism of QFT to the propagation of atomic electron states interacting with bosons like photons. I would claim that this is in error, because the vindication of the diagram technique of QFT requires the assuming of boson or formation statistics for the states involved, to prove Wicks theorem and this fails for Slater determinants. In the past I have got around this by using a Projection technique due to Abrikosov. I would like to present some of the formal issues in connection with this failure, mixing it up with various stories to make the technicalities palatable.
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Friday 30 November 2007
Prof. K Ulrich (Ulli) SchreiberResearch Establishment of Satellite Geodesy Technical University of Munich
New Challenges for Sagnac Interferometry
Characteristic parameters such as sensitivity, scaling factor stability and instrumental drift are usually used to qualify rotational sensors in navigation. In this group of sensors, ring lasers may be considered as the most prominent representatives. Over the years our instruments have matured to resolve Earth rotation to eight orders of magnitude, which puts them near the threshold of actively contributing to space geodesy. Because of the availability of permanent high resolution observations, ring lasers became the enabling technology for the emerging field of rotational seismology (www.rotational-seismology.org) where also Fiber Optic Gyros have their place. This talk will outline the current challenges and applications of Sagnac interferometry in geophysics.
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Friday 23 November,
Veronica Cahyadi, PhD Student, Department of Physics and Astronomy, University of Canterbury
Improving Teaching and Learning in Introductory Physics at the Department
This talk describes some research that I have been involved in this department to help students learn better and instructors teach more effectively. The first study investigated the effects of a teaching approach consisting of interactive engagement activities. The results and implications will be discussed. In the second study interviews with lecturers, teaching assistants and students revealed their perceptions of the utility of real-life materials in instruction. The third study evaluated “Introduction to Physics Education Research” course which aims are to raise instructors’ awareness of issues in learning physics and to improve their knowledge of effective instruction. This talk will hopefully prompt some discussions on further efforts to improve teaching and learning in the department.
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Friday 16 November,
No Seminar - Show Day
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Friday 9 November,
480 Projects 15 minute talks 400-level students present their individual projects Department of Physics & Astronomy
Speaker |
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Subject |
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Supervisor |
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Project |
Emily Brunsden |
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ASTR |
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Assoc Prof Peter Cottrell |
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Regular and semi-regular pulsating stars. |
Matthias Droth |
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PHYS |
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Dr Jenni Adams |
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Probing Planck Scale Physics with IceCube |
Kai Lenz |
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PHYS |
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Dr Juergen Meyer |
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Modelling of the correlation between patient respiration and tumour movement |
Joseph McCartin |
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PHYS |
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Dr Jenni Adams, Dr Suruj Seunarine |
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Local coincidence verification for IceCube |
Christoph Scherer |
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PHYS |
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Dr Ishwaree Neupane |
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Theories of cosmic acceleration: approaches of cosmological Reconstructions Quantum noise in ring lasers |
Mohammed Al Shehri |
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PHYS |
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Dr Jon-Paul Wells |
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Quantum noise in ring lasers |
Vincent Thompson |
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ASTR |
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Prof John Hearnshaw |
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The signal-to-noise ratio of fibre-fed CCD echelle spectra and its effect on raial-velocity precision |
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Friday 2 November,
Associate Professor Simon Brown Department of Physics and Astronomy, University of Canterbury Nano-devices based on atomic clusters I will present an overview of the work done in my group (and at Nano Cluster Devices Ltd) over the last 5 years. The topics covered will include • why nanodevices are needed and why clusters are useful building blocks for them • why picking nanoscale objects up and placing them individually is slow and tedious • how clusters can be "self-assembled" • some of the physics of the assembly processes (including bouncing of nanoscale balls) • the devices we have been able to make, including various kinds of gas sensors .
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26 October 2007
Gavin Milne, A senior physics teacher at Mount Albert Grammar School currently completing his Masters degree in Astronomy and Science Education at the University of Waikato.
Teaching Astronomy in NZ high schools
Secondary school astronomy education is currently limited to a few superficial topics in junior science and some limited NCEA standards in senior science. Mount Albert Grammar School will be the first school in New Zealand to have an entire senior course on astronomy, aimed to lead students into tertiary astronomy and physics study, or careers in astronomy.
A traditional course would be based on a different and predictable areas of knowledge and fact, possibly linked to history and discoveries, and usually organised by topics of ever increasing distances from the Earth, planets then stars then galaxies etc. The new course is based entirely on skills, mainly astronomical imaging, and students will learn the facts almost as a side note, as and when they need them. This course is only possible because of the construction of the Mount Albert Grammar School Observatory – the most advanced observatory in any school in New Zealand.
This talk will discuss the challenges and benefits of such a course, to both our students and education as a whole. It will also discuss the construction of the observatory and its future imaging programs.
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19 October 2007
Dr Graham Hill
Visiting Scientist, Department of Physics, Auckland University
A spectroscopic study of the rapidly rotating pole-on star Vega.
Vega is one of the ten primary photometric standards and the spectrophotometric standard. Calibrated spectrophotometry of the star is used to check the reliability of stellar atmosphere/spectrum synthesis codes.
An extension of these models combined with observation is used to calibrate instruments operating at long wavelengths. An early study (circa 1994) is updated here based on much better data and a comparison made with a 2006 astrometric study. Both these analyses show that Vega is rotating almost pole-on though at differing fractions of the breakup velocity.
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12 October 2007
Peyman Zawar-Reza,
Department of Geography, College of Science, University of Canterbury
Mesoscale Processes and boundary-layer dynamics over Christchurch: a numerical modelling approach
In spite of its ‘clean-and-green’ image, New Zealand suffers from air pollution levels that are considered to present a risk to human health, particularly with respect to PM 10. Air pollution regulation in New Zealand is covered by the Resource Management Act 1991, which requires regional authorities to establish environmental management strategies to address problems of air, land and water quality. Under the powers of this act, the New Zealand Ministry for the Environment issued new and more stringent National Environmental Standards for air pollution to be fully implemented by 2013. Hence, the development of mesoscale models that accurately predict air pollution exposures at the intraurban scale has recently been recognised as a priority area of study. The aim of this seminar is to discuss and evaluate the effectiveness of stat-of-the-art atmospheric models such as The Air Pollution Model (TAPM), Meoscale Model (MM5), and Weather Research and Forecasting (WRF) for simulating boundary-layer dynamics and PM 10 concentrations for the city of Christchurch, New Zealand. With particular emphasis on the effect of soil moisture initialisation on the development of modelled solutions.
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5 October 2007 (Replacement Seminar - 3 Postgraduate Students)
Samuel Whitehead Physics & Astronomy Department, University of Canterbury
MCSS - My CERN Summer Studentship CERN, LHC, CMS, BRM, BCM, BSC - the list of acronyms is endless at the European Centre for Nuclear research. In this short presentation I will discuss my time spent working in the UXC and on the BCM2 detector as part of the BRM group, a subsystem of the CMS detector in the LHC ring at CERN.
Hana Schumacher Physics & Astronomy Department, University of Canterbury
For my MSc I am studying two W UMa type eclipsing binaries: BP Velorum and V752 Centauri and one detached eclipsing binary V392 Carinae. From observations taken at Mt John Observatory's 0.6m OC telescope earlier this year, the corresponding light curves will be compared with models compiled from the Physics Of Eclipsing binaries (PHOEBE) software to obtain various physical parameters for these two Systems.
Rueben Mendelsberg Physics & Astronomy Department, University of Canterbury Photoluminescence of ZnO nanostructures
The use of zinc oxide dates back as far as the 12 th century in Zewar, India. In those early times it was mainly used for healing wounds, treating sore eyes, and for white pigments for paint. Today it is recognized as one of the most promising materials for the next generation of optoelectronic devices.
Here in the physics department we produce self-assembled ZnO nanostructures by eclipse pulsed laser deposition (EPLD). Samples produced by EPLD have superior photoluminescence emission to those produced by standard PLD. Temperature dependent measurements reveal free excitonic emission as well as emission from several donor-bound excitons. Low temperature power dependent measurements show non-linear behaviour of one of the bound excitons in some samples. This behaviour has not been previously reported and has some of the characteristics of stimulated emission. It has yet to be observed in bulk ZnO.
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Monday 1 October 2007
480 Projects
Cheng-Yang Lee |
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Tracy Melzer |
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Schritt Dimitri |
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Thomas Watson |
MAPH |
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MDPH |
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MAPH |
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MAPH |
Dr Dharamvir Ahluwalia-Khalilova |
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Prof Phil Butler |
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Dr Dharamvir Ahluwalia-Khalilova and Dr Ben Martin (MATHS) |
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Dr Dharamvir Ahluwalia-Khalilova |
Development of S-Matrix theory for Elko dark matter |
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2D colour X-ray mammography with Medipix |
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Elko Dark Matter Two Local Incarnations |
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An ab initio investigation of massive vector fields |
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Friday 28 September
480 Projects
Adam Hyndman |
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Daniel Robertson |
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Jeffrey Simpson |
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Juliane Wilcke |
PHYS |
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PHYS |
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ASTR |
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PHYS |
Assoc. Prof. Roger Reeves |
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Assoc. Prof. Roger Reeves |
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Assoc. Prof. Peter Cottrell |
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Dr Richard Watts |
Growth and optical characterisation of MnF2 thin films |
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Growth of thin film photorefractive films |
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Stellar nucleosynthesis and its implications for the evolution of stars in globular clusters |
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Imaging consciousness in the brain: an fMRI and DTI study of binocular rivalry |
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21 September 2007
Professor Keith Horne,Visiting Erskine Fellowship (1 Sept - 31 Oct '07)
Department of Physics & Astronomy. University of St Andrews, Scotland
http://www.st-andrews.ac.uk/~www_pa/
We are fortunate to live in the discovery era of extra-solar planets. Over 250 planets beyond the Solar System are now known, most of which are gas giants found by the Doppler wobble method. Their surprising diversity has transformed our ideas about planet formation. The advent of two further discovery methods, transit photometry and gravitational lensing, makes it likely that we will soon be discovering Earth-mass planets, to determine the abundance or otherwise of habitats like our own. I will review the status and prospects of the discovery methods, which are leading toward a viable search for Life on nearby habitable worlds.
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14 September 2007
Professor Gerry CarringtonHead, Department of Physics, University of Otago
Energy - A perspective on the future in New Zealand From the perspective of a rational individual (me?), better consumer energy efficiency is an attractive possibility for reducing primary energy demand in response to emerging environmental and energy supply constraints. A number of authors argue that efficiency has nothing to do with overall demand, yet some countries have adopted a policy of improving consumer efficiency as the cheapest and safest way to meet their energy objectives. But the task of increasing consumer efficiency is often underestimated and inefficient energy use appears to be deeply embedded in NZ society. In this talk I will present the basic physics of energy efficiency on the small scale, describe the barriers to more efficient energy use on the larger scale and discuss what could be done to support rational responses to our energy problems.
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There will be no seminars during the 2nd Semester break (27Aug-9Sept)
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24 August 2007
Dr Anthony ButlerConsulting Radiologist at the Christchurch Hospital, former University of Canterbury student of the Physics and Astronomy Dept and PhD student of the Electrical Computing Engineering Dept
Bio-medical X-ray Imaging With Spectroscopic Pixel Detectors
The aim of this presentation is to review the clinical potential of spectroscopic X-ray detectors. Images of surgical specimens obtained with a Medipix-2 detector will be presented. A new breed of X-ray detectors is being developed that individually processes photons interacting with a sensor. These are either known as quantum detectors, photon counting detectors, or for the more advanced systems, photon processing detectors. Many of these detectors, such as Medipix-2, allow thresholds to be selected so that only photons within a specified energy range are recorded. New detectors in development, such as Medipix-3, have multiple thresholds within each pixel. These new detectors will allow for routine use of spectroscopic X-ray systems for bio-medical imaging. The significance of spectroscopic X-ray detectors is difficult to predict but insights can be gained by examining both image reconstruction artefacts caused by beam hardening, and the current uses of dual energy techniques in biomedical imaging. Beam hardening artefact is a CT reconstruction artefact that arises due to the approximation that the spectrum of transmitted X-rays is constant regardless of the material being imaged. This artefact poses significant clinical problems in diverse areas including CT pulmonary angiography and muskuloskeletal imaging around metallic implants. It is hoped that with spectroscopic detectors the artefact can be reduced, thus improving diagnostic capabilities. Dual energy angiography is a technique where an infused angiographic contrast agent is identified by its k-edge. Within bio-medical imaging iodine and gadolinium contrast are routinely used for vascular studies and tumour characterisation. Both iodine and gadolinium have k-edges within the energy range of diagnostic X-rays making them easily identifiable with spectroscopic detectors. Potential clinical applications include pre- and post-contrast CT imaging and retention of contrast in tumours such as breast cancer. Different tissues and tumours have different attenuation coefficients over a range of energies. Spectral imaging will translate to better identification and delineation of tumours compared to conventional imaging. While dual energy techniques are well established for bone diseases, for practical reasons they are rarely used elsewhere.
Despite this, spectral information is known to be of benefit for many diseases. Published examples of the use of energy information in mammography include:
- lower energies provide better soft tissue contrast.
- ductal carcinoma has a different attenuation spectrum than fibrous tissue.
- micro-calcification can be better identified for early detection of cancer.
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17 August 2007
Dr Clemency Montelle, Department of Mathematics, University of Canterbury
Crossing the Shadow Theoretical Techniques for Eclipse Prediction in the Ancient World
In all cultures in the ancient world that took an interest in the heavens, eclipses were events of great significance. However, out of all celestial phenomena, they presented the astronomer with the most challenges. Problems that were easy to formulate such as frequency, duration, and amount of obscuration, rested upon more advanced astronomical and mathematical theories than were available: such as spherical trigonometry, parallax, and the measurement of time, to name a few.
This talk will discuss a selection of observation reports and predictions of eclipse times by early astronomers and explore some early attempts to develop and improve theoretical techniques to model eclipse phenomena, particularly those that emerged in the Ancient Near East and India.
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10 August 2007
Prof. Keiichi Akama, Department of Physics, Saitama Medical College,
Saitama, Japan
A field theoretical foundations of the brane induced gravity
"Braneworld" is a picture based on an idea that we live in a 3+1 dimensional hyper-surface embedded in higher dimensional spacetime. "Brane induced gravity" is a model of braneworld gravity which is induced by quantum fluctuations of the matters trapped on the braneworld. Here we investigate a simple field theoretical model based on the Nambu-Goto action for the brane, and show how it realizes the brane induced gravity.
It turns out that the negative tension of the original N ambu-Goto brane can consistently give the right signatures for the kinetic terms of the matter, for the attractive gravity, and for fine tuning of the cosmological term.
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3 August 2007
Dr David Wiltshire Senior Lecturer of Physics, Physics & Astronomy Department, University of Canterbury
Gravitational energy as dark energy: Towards a new concordance cosmology without Lambda
In previous talks in the Department, I have outlined my new proposal to averaging the actual inhomogeneous universe, to explain cosmic acceleration as an apparent effect due to quasilocal gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe. In this talk I will give an introduction to the proposal, and then concentrate on new quantitative results, and their implications for cosmology.
Concordance values of cosmological parameters are found which simultaneously fit Type Ia supernovae luminosity distances, the effective comoving baryon acoustic oscillation scale seen in galaxy clustering statistics, and the angular scale of the sound horizon relevant to the Doppler peaks in the CMB anisotropy spectrum. This is achieved despite an average negative spatial curvature at late epochs, potentially resolving the anomaly associated with ellipticity in the CMB anisotropies. The baryon density fraction obtained from primordial nucleosynthesis bounds can be significantly larger, yet consistent with primordial light element abundance measurements, including lithium. Ratios of non-baryonic dark matter to baryonic matter of 3:1 are found as a best fit. The expansion age is increased, allowing more time for structure formation. Other unique predictions are made, including a quantifiable variance in the Hubble flow below the scale of apparent homogeneity, consistent with the observed “Hubble bubble” feature.
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27 July 2007
Dr. Leslie Young Southwest Research Center, Boulder, Colorado, USA Deputy Project Scientist. New Horizons
Pluto's changing atmosphere: stellar occultations and the New Horizons mission to Pluto
Pluto's nitrogen atmosphere is in vapour-pressure equilibrium with the nitrogen ices on the surface. As Pluto recedes from the sun and the sub-solar latitude moves poleward, changes in the surface temperature leads to rapid and significant changes in the atmospheric thermal structure, dynamics, and overall pressures. For example, Pluto's atmosphere has doubled in pressure between its discovery in 1988 and more recent observations in 2002, 2006, and 2007. The best way to study Pluto's current change is with the technique of stellar occultation, where Pluto and its atmosphere pass between an observer and a distant star. The defocusing of the starlight allows us to derive pressure and temperature profiles of Pluto's atmosphere. We observed a Pluto occultation from Australia and New Zealand in 2006, and are attempting another observation on July 31 of this year. The time-base of occultation studies will tie in with the New Horizons mission to Pluto, which will give us a rich snapshot of Pluto's atmosphere and surface in 2015.
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20 July 2007
Asst. Prof. Chiang-Mei Chen
National Central University , Taiwan
Extremal Black Holes in 4D Gauss-Bonnet Gravity (view abstract)
We show that a four-dimensional Einstein-Maxwell-Dilaton-Gauss-Bonnet gravity admits asymptotically flat black hole solutions with a degenerate event horizon of the Reissner-Nordström type
. Such black holes exist for the dilaton coupling constant within the interval 
. Black holes must be endowed with an electric charge and (possibly) with magnetic charge (dyons) but they cannot be purely magnetic. Purely electric solutions are constructed numerically and the critical dilaton coupling is determined to be 
. For each value of the dilaton coupling 
within this interval and for a fixed value of the Gauss--Bonnet coupling 
we have a family of black holes parameterized by their electric charge. Relation between the mass, the electric charge and the dilaton charge at both ends of the allowed interval of 
is reminiscent of the BPS (Bogomolny-Prasad-Summerfield) condition for dilaton black holes in the Einstein-Maxwell-Dilaton theory. The entropy of the DGB extremal black holes is twice the Bekenstein-Hawking entropy.
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6 July 2007
Professor Daniel Sudarsky
National Autonomous University of Mexico
Cosmological Mysteries and the Problematic Quantum Origin of the Cosmic Structure.
We will go through a brief review of the current status of the most important questions of cosmology, focussing at the end on a critical analysis of the current understanding of the origin of structure in inflationary scenarios. Then we will present a phenomenological model constructed to address the problematic issues, which is inspired on R. Penrose's proposal for a possible modification of Quantum Mechanics associated with Quantum Gravity and show that these ideas are in fact susceptible to being empirically explored.
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29 June 2007
Professor Rick BluteMathematics Department, University of Ottawa, Canada
Categorical structures in algebraic quantum field theory.
Algebraic quantum field theory, as formulated by Roberts and his colleagues, is an assigment of a C*-algebra, the algebra of local observables, to certain open sets in spacetime. Properties of the field theory are most easily expressed in terms of category theory, an algebrac theory originating in topology. Furthermore, categorical techniques are crucial in the analysis of the field theory. This includes a theorem of Doplicher and Roberts, which is used to recover the gauge group of the theory. The talk will begin with an introduction to category theory.
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22 June 2007 - No Seminar today
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15 June 2007
Pauline Harris (Rongomaiwahine Physics and Astronomy Department University of Canterbury ) Maori Astronomy (Tatai Arorangi) experts (Tohunga) have a strong tradition of watching the stars and being familiar with the rising and setting of constellations throughout the year. For Maori in the past the relationship to the heavenly bodies was extremely spiritual; they were seen as an integral part of why we were here and where we would return when we passed from this life to the next. The patterns of their movement signified periods of time during the year to embark on different practices. The Maori New Year which is on the 16th June, this Saturday is signified by the first new moon after the pre-dawn rising of Matariki (the Pleiades). It is a very significant time of year traditionally and in a modern context symbolising the continued revitalisation of traditional practices for Maori.
I will give you an insight into this world, how we related with the heavenly bodies in regards to tracking time, including the Matariki and how we are connected to them through whakapapa (lineage).
15 June, 2007
CANCELED DUE TO DELAYED FLIGHT -
Munya Andrews
Author of "The Seven Sisters of the Pleiades" and amateur astronomer
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8 June 2007
Fred Johnson MNZM, FIPENZ, C Eng, MIET The New Zealand Association of Radio Transmitters Inc (NZART)
The Electromagnetic Wave – Introductory Demonstrations for the Classroom
Electromagnetic waves surround us. They are unseen and their characteristics must be found by exploration. Inexpensive apparatus and “hands on” experiments have been developed to apply radio technology principles to investigate the electromagnetic wave and how it is used in many applications today. Companion experiment sheets are provided to guide the experimenter.
A circuit module using surface-mounted devices, with a battery, switches, and other items are used to generate a radio wave. Various launch methods and the propagation of the wave with the effects of various materials in its path can be observed. A meter and a diode are used to detect our signal. A special licence for this transmitting equipment is not required.
This class-room radio link can illustrate how modulation of the signal can transfer information, how remote-controls work, how a TV aerial works, and how aerial designs can improve signal directivity and extend the working distance. The polarisation of a signal, reflections, standing waves and wavelength measurement can be investigated.
Explanatory booklets can be downloaded from the web and provide theory explanations with many diagrams and full construction details.
The cost of this apparatus is kept small by the innovative use of readily-available materials. There is opportunity for developing further projects and radio links to support other purposes and Science Fair opportunities.
The New Zealand Association of Radio Transmitters Inc (NZART), the radio amateurs’ organisation, promotes interest in the science and technology of wireless communication and formed the NZART Radioscience Education Trust to promote and encourage education in radioscience. The Trust supports Science Fairs with prizes and contributions to school projects and support to the development of the apparatus in this presentation.
For students with the interest and the drive to go a little bit further, details are given of a world-wide-recognised qualification within the reach of any youngster: the amateur radio examination. This qualification is an indicator of interest and is useful preparation for a career in the telecommunications and electronics industry. It is independently examined from a public-domain question-bank, which with free study material, is available from the web.
This is a display of the wave generation, propagation and reception apparatus and a PowerPoint presentation.
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1 June, 2007
Prof. John Hearnshaw
Department of Physics & Astronomy,
University of Canterbury
The 25 greatest discoveries in astronomy and astrophysics of the 20th century
I present a list of what I consider to be the 25 greatest discoveries in astronomy and astrophysics of the 20th century. My criteria for selection were to exclude planetary exploration of the solar system by spacecraft and to include discoveries which were especially influential in opening up new understanding, or revealing new classes of phenomena. I put these discoveries in my personally estimated order of importance. I then analyse the papers arising from these discoveries by the area of astrophysics to which they pertain, by the year of publication, by the age of the author(s) and by the country where the authors were working.
I conclude that the most productive years for astronomy in the 20th century were between 1911 and 1920 and again in the 1960s. In spite of the 10-fold increase in publication rate at the end of the century relative to the beginning, the rate of publication of the most seminal papers has actually declined, in spite of the obvious advances in technology. I offer an explanation for this observed phenomenon.
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25 May, 2007
Dr. Steven Jamison
Accelerator Science and Technology Centre,
STFC Daresbury Laboratory, UK
Ultrafast Lasers and Particle Accelerators
The upcoming generation of particle accelerators needs to operate with ultrashort (sub 100fs) highly relativistic bunches. In entering this femtosecond regime, a myriad of new challenges have arisen;
- How do you measure the temporal profile of such an ultra-relativistic bunch, travelling at the speed of light, and do so non-destructively?
- Can clocks be made stable enough for the required fs timing signals, and how do you distribute such signals around a 30km long machine?
- How can we manipulate the phase-space of the particle bunch on these time scales?
In this seminar I will give examples of the solutions to such questions that are being found within the field of ultrafast laser physics. I will also discuss how, in parallel to addressing the accelerator "machine physics", fundamental issues in laser physics, laser-matter interactions, and laser driven particle acceleration, are being explored.
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Friday 18 May, 2007
Dr Alan Walton,
Visiting Erskine from Cambridge University
From Babbling Brooks to Sonoluminescence; the Physics of Bubbles in Liquids
Unlike their nineteenth century counterparts, today's physicists often lack the curiosity to explore the sights and sounds of the Earth-bound natural world.This seminar will describe the experimental and theoretical studies aimed at discovering the origins of of the sounds produced in a wide range of natural processes ranging from babbling brooks, through dripping taps, to boiling kettles. It will be shown that bubbles are the root cause. The seminar will also describe the inverse process in which sound is fed into a liquid, leading to the emission of light and -some would claim - to nuclear fusion in a test tube.
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Friday 11 May, 2007
Dr Richard Watts
Physics & Astronomy Department, University of Canterbury
Imaging the Brain: A Physics Perspective
The human brain weighs less than 1.5kg, and yet contains roughly 100 billion neurons. It uses nearly 20% of the body's energy, despite accounting for only 2% of its mass. I will present a physicist's view of how we can start to understand this most complex of machines through the use of medical imaging and specifically MRI. Very preliminary results of functional and diffusion MRI from the first 3 Tesla MRI scanner installed in New Zealand, recently installed in Christchurch) will be presented.
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Friday 4 May, 2007
Professor Pál Ormos,
Institute of Biophysics , Biological Research Centre Hungarian Academy of Sciences, Szeged, Hungary (Visiting Erskine 28 Feb- 31 May)
Optically driven micromachines for biotechnology Photopolymerisation offers a relatively simple method to produce microscopic particles of arbitrary shape that are practical to expand the possibilities of optical manipuation. There are different ways to influence the orientation of non spherical objects in the optical traps. For example, propeller shaped micrometer sized rotors are rotated in optical tweezers, while flat objects are oriented in traps formed by linearly polarized light. The force and toque exerted by these devices falls in the range of those occuring in biology. Consequently, such elements and the possibilities opened up by their use would find numerous applications biology, both in fundamental science and biotechnology (lab-on-a-chip devices) by realising new types of manipulation. Photopolymerisation is also a practical method to create microchannels, microvessels, as well as optical waveguides. By the combination of these elements complex, fully integrated systems are built where the manipulation and observation of single molecules, cells or other biological objects of up to micometer size can be realised.
I will show the function of the different elements and how they can be applied in single particle experiments. In addition, I will also show how we try to build optically controlled microfluidic systems by their combination.
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Monday 16 April
Professor Roger Clay
School of Chemistry and Physics,
University of Adelaide
Cosmic Bullets, High Energy Particles in Astrophysics
The Universe is filled with energy in many forms. One of the most intriguing forms is energetic particles, known as cosmic rays. Although cosmic rays have been seriously studied for 100 years, they are not completely understood. Their continued study remains important since it seems that they make up an important component of the energy around us in our galaxy, their energy density outside our galaxy is poorly known, and we have no real idea of how Nature produces the particles with the highest energies. This talk will introduce the study of cosmic rays over a wide range of energies and will then concentrate on some aspects of our understanding of the highest energy particles, through attempts to reproduce the measured properties of cosmic rays based on astrophysics as we presently understand it.
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13 April 2007
Prof. Raymond R. Volkas School of Physics, The University of Melbourne
The Standard Model on a domain wall brane Our universe might be a brane or submanifold embedded in a higher dimensional spacetime. The most obvious field-theoretic model for a brane is a domain wall (concept and terminology borrowed from condensed matter physics) existing in an underlying 4+1-dimensional spacetime. The domain wall is a solitonic scalar field configuration. The major issue is how to confine or localise fields to the domain wall so as to reproduce an effective 3+1-dimensional world. After reviewing the general topic of extra dimensions and branes, I describe how one might actually write down a 4+1-dimensional theory that has an effective 3+1-dimensional Standard Model as one of its
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30 March 2007
Professor Fulvio Melia University of ArizonaVisiting Erskine Fellow 24 Feb-24 Apr 07
High-energy Activity at the Galactic Center
Once hidden almost completely by the intervening gas and dust along our line-of-sight, the Milky Way's central black hole first manifested itself as a radio point source, then as a variable infrared object and, most recently, as a dynamic emitter of X-rays, including an intriguing periodic modulation to suggest emission not far from its event horizon. There are even indications that it may be the dominant accelerator of relativistic protons, accounting for the central (HESS) TeV source and, possibly, the diffuse TeV emission associated with molecular clouds along the Galactic plane. In this talk, we will discuss work in progress to understand what this high-energy activity is revealing about the environment within tens of Schwarzschild radii of the central supermassive object.
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23 March 2007
Dr Attila Meszaros
Hungarian astronomer working in Prague at the Charles University.
Cramer theorem and the gamma-ray bursts
At the beginning of the seminar a brief survey of the topic of the gamma-ray bursts will be given. Then a paper of author will be presented (A&A, 401, 129, 2003). This paper uses a mathematical theorem (Cramer theorem) in order to prove that the short and long gamma-ray burst are physically different phenomena. This procedure in the astronomy is so surprising and curious that this method can be interesting for the non-specialists, too .
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16 March 2007
Dr Damian Murphy Australian Government Antarctic DivisionErskine visitor with the Physics & Astronomy Department 19 Feb – 13 April
Tides in the middle atmosphere above AntarcticaThe mesosphere and lower thermosphere (MLT) region is only 70-100 km above our heads but it is remote enough to be poorly characterized. A variety of processes change it on time scales of minutes, hours, days and seasons, and neither current ground-based or space-based observations can tell us what is going on at the spatial and temporal scales needed for a complete understanding. Expansions of the multinational MF radar network in Antarctica (which includes the Scott Base radar) have shown that atmospheric tides in the MLT are more complex than originally thought and are providing some clues as to why. The observed longitudinal variation in tidal amplitude can be explained by combinations of tides with various zonal (constant latitude) wavenumbers, and their mix and seasonal variation can be measured. This informs investigations of their source and the cause of their temporal variability. In this seminar, the evolution of our knowledge of atmospheric tides will be described along with techniques used to gain insight from our radar observations.
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9 March 2007
Adam Cath
Physcial Sciences Library, UC
Physical Sciences Library:-Roadshow '07 Physical Sciences Library will provide an introduction to the library's people, resources and services, highlighting recent changes and library news relevant to the department. There will be some discussion of changes taking place within the UC Library and in the larger world of information and on how resulting library collection decisions may impact upon the Department. The session will conclude with a question and answer session and hopefully some one-on-one between library staff and the department. All welcome!
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2 March 2007
Peter SzekeresVisiting Research Fellow at the School of Chemistry and Physics, University of Adelaide
Cosmological networks A well known way of creating an inhomogeneous model of the universe is to remove an expanding spherical region of a standard Friedmann-Lemaître model and replace it with the vacuum Schwarzschild solution corresponding to the missing mass. This can be done simultaneously in any number of regions, commonly referred to as the "Swiss-Cheese" model. Contrary to common belief, the vacuum regions are not black holes, but are actually white holes which can also act as topological bridges connecting separate universes. This makes possible a bewildering variety of cosmological models which could be described as "networks" of interconnecting universes.
22 February 2007
Bridget Ingham
Industrial Research Limited, Lower Hutt, New Zealand
Stanford Synchrotron Radiation Laboratory, Menlo Park, CA, U.S.A.
An Overview to Synchrotron Techniques and Applications
With the construction of the Australian synchrotron nearing completion, New Zealand researchers will soon have improved access to a world-class, high-flux x-ray source. Synchrotrons are used to perform experiments that are difficult or impossible with conventional laboratory x-ray sources – as results of limitation in flux, energy resolution, spatial resolution, and so forth. Due to the high coherence of synchrotron light, other unique possibilities are also available such as polarised x-rays and ultra-fast x-ray pulses.
This seminar will present a general overview of synchrotron radiation and techniques, including recent examples from the fields of physics, chemistry, materials science, biology, environmental science, corrosion, nanotechnology – to name but a few – in order to highlight the possibilities that exist in performing research at synchrotron facilities. Real time, in situ measurements using various techniques will also be described.
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Monday 19 February (Special Seminar)
J. Akola
Nanoscience Center, University of Jyväskylä, Finland
Gold Atoms and Clusters on Defected Graphite (0001) by Density Functional Theory Possible ways for attaching gold atoms and clusters (N=6) on defected graphite (0001) have been studied using the density functional theory, a generalized gradient correction for the exchange-correlation energy, pseudo potentials and periodic boundary conditions [1]. Apart from pristine graphite (0001), three types of surface defects have been considered: a surface vacancy (hole), a pyridine-like defect comprising three grouped nitrogen atoms, and a direct replacement of C atom with either N or B. Results for both Au and Au 6 imply that the surface vacancy is able to form chemical bonds with Au as the three nearby carbons align their dangling bonds towards the gold particle (binding energy 2.4-2.6 eV). A similar hole-like construction with three pyridinic N atoms results in a significant polarization (1.1-1.2 eV), whereas binding with faultless graphite is weak (0.3-0.5 eV). Several Au 6 isomers in different orientations are tested on substrate, and coordination through corner atoms is found energetically favourable. Analysis of the charge density shows no considerable charge transfer, and the net charge on Au 6 ranges between -0.1e and +0.2e. The detailed charge accumulation/depletion plots reveal interesting polarization effects between Au 6 and substrate [2].
In addition, I shall discuss the properties of alkali metal (Li, Na, K, Rb, and Cs) atoms, clusters and (2x2) monolayers on graphite. The adatoms are observed to bind at the hollow site (graphite hexagon), with Li lying closest to (1.84 Å) and Cs farthest (3.75 Å) from the surface. The adsorption energies range between 0.55 and 1.21 eV, and the energy ordering of the alkali-metal adatoms is Li>Cs
Rb
K>Na. The formation (cohesion) energies of (2×2) monolayers range between 0.55 and 0.81 eV, where K has the largest value, and increased coverage weakens the adsorbate-substrate interaction (decoupling) while a two-dimensional metallic film is formed. Analysis of the charge density redistribution upon adsorption shows that the alkali-metal adatoms donate a charge of (0.4–0.5)e to graphite and the corresponding values for (2×2) monolayers are ~0.1e per atom. The transferred charge resides mostly in the 
bands (atomic p z orbitals) of the outermost graphene layer [3,4].
Festkörperforschung Stuttgart 1997-2005. http://www.cpmd.org. [2] J. Akola and H. Häkkinen, Phys. Rev. B 74, 165404 (2006). [3] K. Rytkönen, J. Akola, M. Manninen, Phys. Rev. B 69, 205404 (2004). [4] K. Rytkönen, J. Akola, M. Manninen Phys. Rev. B 75, 075401 (2006).
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16 February 2007
Prof Sylvie Vauclair
Laboratoire d'Astrophysique, Observatoire Midi-Pyrenees, Toulouse, France and Professor of Astrophysics at the Universite Paul Sabatier, Toulouse.
Asteroseismology of exoplanets hosts stars
Asteroseismology recently became a powerful tool for testing the internal structure of solar-type stars. Meanwhile, more than 200 exoplanets have now been discovered, a number large enough to allow for statistics.
Comparisons between exoplanets hosts stars and stars without detected planets give evidences for some differences between them. In particular exoplanets hosts stars are overmetallic compared to the Sun by a factor about two. I will give a general summary of these questions, and I will present the first asteroseismic analyses and results we obtained for exoplanets hosts stars.
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26 January 2007
Professor Taekoon Lee
Kunsan National University , Korea
Puzzles with P-wave charmed mesons Contrary to the potential model predictions, the recently observed P-wave charmed mesons do not exhibit spin-orbit inversion and have much smaller masses and decay widths than predicted. We show that chiral one loop corrections must be included in potential model, and some of the puzzles can be resolved once the loop corrections are taken into account.
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