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Tuesday, 15th December
IceTop - Cosmic Ray physics at the South Pole
Hermann is leading the IceCube/IceTop group at Humboldt University, Berlin. He has spent the last month at South Pole working on the IceTop installation. He will be visiting Canterbury University on Tuesday before returning to Germany.
11th December 2009
What does sustainability have to do with physics?
How do we see the world and our place in it?
The word ‘sustainability’ has become increasingly prominent in recent years. It is seen by some as just another hollow buzzword, and seen by others as a non-negotiable requirement to ensure the long-term survival of humans and much of life on Earth. The most commonly used definition of sustainable development is “meeting the needs of the present generation without compromising the ability of future generations to meet their own needs.” What does this really mean and what relevance does it have to physics?
Kate Hewson, UC’s Sustainability Advocate, will explore the modern concept of sustainability from various philosophical, social, and physical angles, and outline some of the challenges sustainability poses to modern techno-industrial societies. She will invite discussion on what the modern concept of sustainability might mean for people with an understanding of physics.
Friday, 4th December
Stroke: Diagnosis and Treatment using Ultrasound Brain strokes happen when the arteries leading to the brain are blocked or rupture. Such acute events have to be promptly treated within a three hour window after onset of symptoms: "time is brain". Therefore patients admitted to an acute stroke hospital have to be both diagnosed and treated promptly as well as being monitored during medication. Also, stroke prevention with respect to recognising and reducing risk factors like hypertension and arteriosclerosis is a high priority. Furthermore, during heart and vascular surgery the number of embolic events should be reduced as far as possible to improve outcomes and increase the benefits for the patient.
One method for monitoring acute stroke patients or to improve risk management in prevention and surgery is by means of ultrasound Doppler instrumentation. This helps to record blood flow to the brain and to detect emboli, which are stuck in or are just entering the cerebral arteries. Even more, as a non-invasive application such ultrasound equipment can accelerate the thrombolitic treatment for embolysis. In parallel this insonation allows the possibility to control the effectiveness of the medical treatment by drugs.
After a short introduction to basic anatomy in cerebral circulation new ultrasound instrumentation techniques are presented including automatic transducer positioning to allow long-term monitoring of the cerebral basal arteries in the Circle Willis in acute stroke patients. In addition, the application of multi-frequency-signals processed by special short-term spectral analysis can differentiate between more or less dangerous emboli entering the cerebral circulation. These new features help e.g. to improve operation techniques during open heart and bypass surgery. Reducing the number of emboli decreases the risk of cognitive deficits or even a stroke. Furthermore, in patients with artificial heart valves the monitoring of dangerous emboli allows for better and optimal doses of medication. Such instrumentation techniques developed in cooperation with university hospitals are just being transferred from research settings to clinical routine in order to increase the benefits for patients.
Friday, 27 November
Professor Geoff Dougherty, Applied Physics and Medical Imaging, California State University Channel Islands 'Currently on a Fulbright Senior Scholarship from the Australian-American Fulbright Commission to undertake six months research at Queensland University of Technology (QUT), Brisbane.
Medical Imaging - An Illustrated Overview
The rapid and continuing progress in computerized medical image reconstruction and the associated developments in analysis methods and computer-aided diagnosis have propelled medical imaging into one of the most important sub-fields of scientific imaging. As well as producing anatomical images, images of physiological function provide fresh diagnostic possibilities. After a brief overview of imaging modalities and an indication of the breadth of current research, a few case studies including bone quality (in osteoporosis), cartilage degradation (in osteoarthritis), retinal tortuosity and spinal curvature (in scoliosis) will be presented. Some of the challenges and ongoing developments will be outlined.
Additional Seminar - Thursday, 26th November
Dr. Jarita Holbrook
University of Arizona
Hubble's Diverse Universe
A new documentary film focusing on ten African- and Hispanic-American astrophysicists, their scientific research, their education, and their lives as astrophysicists. They share their personal stories and give advice about how to succeed in the sciences. The film touches on some of the unique situations faced by minority scientists in the United States. The trailer can be seen online at: http://www.u.arizona.edu/~holbrook/HubbleT.wmv and on YouTube.com.
BIO: Dr. Holbrook, who is executive producer of the film and appears in it, holds a Ph.D. in Astronomy & Astrophysics and is currently a researcher at the University of Arizona. In 1997, she began doing research on people and their relationship to the night sky. Quickly becoming an expert on Africans and their sky knowledge, she is the lead editor on "African Cultural Astronomy" published by Springer Press (2008). Her current research focuses on the relationship that people in developed nations have with the night sky, astronomers and their changing relationship to the night sky, and the lives of women and minority astronomers. Dr. Holbrook is also the current president of the Association of Women Faculty at the University of Arizona, Vice Chair of the Historical Astronomy Division of the American Astronomical Society, Vice President of the European Society for Cultural Astronomy (SEAC) and on the executive committees of the National Society of Black Physicist (NSBP) and the International Society for Archaeoastronomy and Astronomy in Culture (ISAAC). For
IYA2009 she is chair of the Cultural Astronomy & Storytelling group for the United States.
Friday, 20th November
Dr Ricard Watts, Senior Lecturer, Physics and Astronomy Dept, UC
Motion is often the cause of artifacts in MRI scans, due to relatively long acquisition times. However, motion can also be the source of useful contrast. In this presentation I will explain some techniques that rely on the motion of water and blood to generate clinically useful information. Specifically, I will concentrate on the measurement of water diffusion, blood perfusion and flow, all of which can be measured quantitatively and non-invasively.
Friday, 13th November - Show Day - public holiday
Thursday, 12th November
Robert P. Kirshner
Clowes Professor of Science, Harvard University
Fundamentals of Supernova Cosmology: Since the surprising discovery of cosmic acceleration in 1998, observations have converged on a picture in which the universe has ~2/3 dark energy and ~1/3 dark matter. Ordinary baryons, lost in the round-off error, are only about 4% of the mass-energy in the universe. Now our effort has shifted to determining the properties of the dark energy. Is dark energy a constant, like a modern version of Einstein's cosmological constant, or has it changed over cosmic time? Supernova samples are now large enough that systematic errors dominate over statistical uncertainties, so better understanding, not just a larger sample, is required to make progress on this question. New observations carried out at near-infrared wavelengths promise to reduce these errors and lead to a more certain knowledge of the nature of dark energy. This talk will sketch the present constraints on dark energy, illustrate how these can be improved with near-infrared measurements of supernovae, and speculate on the best strategy for future measurements with the proposed Joint Dark Energy Mission.
Friday, 6th November
University Centre for Teaching and Learning (UCTL) staff member, Canterbury University
Investigating astronomy faculty pedagogical thinking: University faculty typically are appointed based on their research record, rather than their teaching experience. Yet, as teaching staff, they make pedagogical and curricular decisions on a daily basis. This study explores the pedagogical thinking of five astronomers who teach the HR diagram as part of the introductory course for non-science majors in the USA. Results indicate a strong emphasis on affective and process goals, rather than content for the whole course, that teaching the HR diagram offers a variety of ways to address those goals, and that participants used similar analogies to address the physical concepts underlying the HR diagram.
Friday, 30 October
Professor John Hearnshaw, Astronomy Lecturer, Physics and Astronomy Dept, University of Canterbury
Can we find Earth-mass planets orbiting our nearest star, alpha Centauri? I will describe a new programme at Mt John that aims to find Earth-mass planets orbiting either alpha Cen A or B, which are solar type stars in a well known binary. We are measuring precise radial velocities using the Hercules spectrograph, which I will describe. About 30,000 spectra at S/N ~ 500:1 giving 3 m/s precision will be needed over 3 years. Theoretical studies show that Earth-mass planets can have stable orbits to 3 AU and that such planets will form from a proto-planetary disk, for a wide range of initial conditions.
Friday, 23rd October
In‐house discussion on re modelling the seminar/tea room.
Discussion led by Dharamvir Ahluwalia
Come along meet and question the consulting architect and give your opinions.
Tuesday, 20th October (Additional Seminar)
Photon Emission near Superconducting Bodies and Atom Chips: As was already pointed out by E.M. Purcell in 1948, the rate of spontaneous emission of atoms will be modified due to the presence of a dielectric body.
Spontaneous emission can be thought of as a physical process, where the emission of a photon is stimulated by vacuum fluctuations. The presence of a medium will change the properties of the vacuum and, hence, also the rate for decay processes. This so called Purcell effect has been one of several central topics in the field of modern experimental cavity quantum electrodynamics.
In current investigations and engineering of nano-scale atom microtraps, this issue is also of fundamental importance since such spontaneous emission processes, due to hyperfine spin-flip transitions, have a direct bearing on the stability of atom chips.
In the present talk, we give a brief introduction to some of these issues in terms of photon emission due to a magnetic spin-flip transition of a two-level atom in the vicinity of a dielectric body like a normal conducting metal or a superconductor. In the analysis of this physical system one has to address issues like the notion of a photon propagating close to or in a dissipative medium. A simpler but analogues problem is how to quantize a damped harmonic oscillator.
For temperatures below the critical temperature of a superconductor, the corresponding spin-flip lifetime can be boosted by almost twenty orders of magnitude as compared to the case of a normal conducting body! This recent finding of ours has opened up the window for the design of new superconductor based atom chips. We also report on some recent work on the related attractive (!) Casimir-Polder force.
16th October (Friday)
What is a Photon – A mind-boggling concept? : Recent developments in electronic and optical technology have made it possible to experimentally realize well localized ONE-photon states.
In this talk, directed to a general audience, I will first remind ourselves about the basic rules of quantum mechanics and then discuss in what sense quantum-mechanical interference of ONE-photon states has been experimentally verified. Then I outline a relativistic and quantum-mechanical description of SINGLE photons and show how the experimentally verified Berry phase of linearly polarized light naturally emerges in such a framework. Geometry, including non-commutative aspects, and quantization are connected in this approach.
The use of t'Hooft-Polyakov non-Abelian magnetic monopoles finds here an amazing application.
If time permits some aspects of the space-time evolution of a localized ONE-photon wave-packet will also briefly be touched upon.
The Origin of High Magnetic Fields in White Dwarfs: White dwarfs with surface magnetic fields in excess of 1MG are found as isolated single stars and relatively more often in magnetic cataclysmic variables. Some 1,253 white dwarfs with a detached low-mass main-sequence companion are identified in the Sloan Digital Sky Survey but none of these is observed to show evidence for Zeeman splitting of hydrogen lines associated with a magnetic field in excess of 1MG. If such high magnetic fields on white dwarfs result from the isolated evolution of a single star then there should be the same fraction of high field white dwarfs among this SDSS binary sample as among single stars. Thus we deduce that the origin of such high magnetic fields must be intimately tied to the formation of cataclysmic variables. The formation of a CV must involve orbital shrinkage from giant star to main-sequence star dimensions. It is believed that this shrinkage occurs as the low-mass companion and the white dwarf spiral together inside a common envelope. CVs emerge as very close but detached binary stars that are then brought together by magnetic braking or gravitational radiation. We propose that the smaller the orbital separation at the end of the common envelope phase, the stronger the magnetic field.
2nd OctoberKurt Baier, Visiting Erskine Fellowship, from the Department of Radiotherapy at the University of Wuerzburg.
The life of Wilhelm Conrad Roentgen: On the 10th December 1901 the first Nobel Prizes were awarded. Wilhelm Conrad Roentgen was the very first person to receive this diploma and medal from the hand of the Crown Prince - later to become King Gustaf V -- at the Musical Academy in Stockholm.
Wilhelm Conrad Roentgen, was the first scientist to observe and record X-rays and is easily the best-known Nobel Laureate to have worked at the University of Wuerzburg. The number of Nobel laureates related to Wuerzburg in the meantime has increased to 14. As a member of this university, I would like to take the opportunity to provide a few brief insights into his life and achievements.
Karen Carthew (PBRF Advisor - College of Engineering/College of Science)
PBRF presentation and discussion time. The Performance-Based Research Fund (PBRF) is one of the main sources of government funding for the tertiary education sector and its primary goal is to encourage and reward research excellence. The next PBRF Quality Evaluation will be held in 2012 and will be a full round; all eligible staff will be assessed on evidence from 1 January 2006 to 31 December 2011. This talk will outline the construction and assessment of evidence portfolios. There will be plenty of time for questions and discussion.
18th September 2009Dr Achim Weiss - Visiting Erskine Fellow (1 September - 30 October) Max Planck Institute of Astrophysics
A systematic look at the Initial-Final Mass Relation:The Initial-Final Mass Relation (IFMR) for low- and intermediate- mass stars connects the beginning and end of stellar evolution.
It is important for an assessment of the importance of mass loss, for the final fate of stars, the types of supernovae that can be expected, but also for the internal physics of stars, as will be shown. Its determination depends on a variety of observational data and theoretical models. In both fields large progress has been made in recent years such that a new look at the IFMR was warranted, about which I will report. In particular, I will discuss systematic uncertainties, which are usually ignored, and present robust and tentative results. One of them is that from the IFMR we do not see evidence for the existence of super-AGB stars.
11 September 2009
A Harvard Video Colloquium presented by D. V. Ahluwalia
Gabriella Sciolla (MIT)
Dark Matter is from Cygnus: in search of a wind of Dark Matter in the Milky Way.
4 September 2009
Amanda Karakas, Research School of Astronomy and Astrophysics, ANU
Nucleosynthesis in Red Giant Stars: For low and intermediate-mass stars (with initial masses between about 0.8 to 8 solar masses) the most important nucleosynthesis occurs when stars evolve off the main sequence to the giant branches. It is during the asymptotic giant branch (AGB) phase of stellar evolution that the richest nucleosynthesis occurs. This is driven by thermal instabilities of the helium-burning shell, the products of which are mixed to the stellar surface by recurrent mixing episodes. Heavy elements can be synthesized during the AGB by the slow neutron capture process and is responsible for about half of all elements heavier than iron. In this talk I will describe the evolution and nucleosynthesis of AGB stars, with a focus on current problems and uncertainties surrounding the production of heavy elements.
I will present new results comparing theoretical predictions to the heavy element composition of planetary nebulae and metal-poor Halo stars. I will finish with a discussion of uncertainties and future work.
Tuesday, 25 to Wednesday 26th August
Physics and Astronomy Dept Conference
Friday, 21st August
Turbulence profiling at Siding Spring and Las Campanas Observatories: I will discuss the observations and implications of the atmospheric optical turbulence profile performed at Siding Spring Observatory (SSO), Australia, and Las Campanas Observatory (LCO), Chile. Knowledge of the atmospheric turbulence is critical in the simulation, design and performance of astronomical adaptive optics (AO) systems. Of interest to the Australian astronomical community is the installation of AO systems at SSO that may lead to better science and extend the life of the observatory (despite the relatively moderate seeing and the modest sized telescopes). Of interest to the Giant Magellan Telescope (GMT) community is the predicted performance and design of AO systems for the GMT 24.5 m telescope to be built at LCO.
Of keen interest is the structure of the ground-layer turbulence below 500 m at LCO for ground-layer AO (GLAO) instruments for the GMT.
To collect our turbulence profile observations we used a custom-built instrument and real- time software based on the SLODAR method. The SLODAR method involves an inverse-problem where the turbulence profile is estimated from time-averaged spatial cross-covariance of the local optical wavefront gradients using Shack-Hartmann observations of a double star.
Friday 14 August
Professor Chris McConville, Visiting Erksine Fellow with the UC Electrical and Computing Engineering Dept from the Surface and Interface Science Group, Dept of Physics, University of Warwick
Quantum Well States at Oxide and Nitride Surfaces: The existence of quantized states at the surfaces of semiconductor materials has been known for some time. For example, Shubnikov-de Haas oscillations can be observed in a 2D electron gas created in a Si MOS structure and similarly, electron tunnelling in an InAs MOS structure can be used to map out the Landau levels as a function of magnetic field. However, these approaches require the formation of a device structure i.e. oxide, contacts, etc. before any observations can be made. In contrast, we have used a form of photoelectron spectroscopy to investigate the surface electronic structure of a range of oxide and nitride semiconductor materials to directly probe quantum well states. Each has a high concentration of accumulated electron at their surfaces and the quantized states are intrinsic properties of these materials. I will briefly review the early evidence for the existence of quantized states in semiconductors and present some of our recent work on InN, CdO and In2O3 surfaces before drawing some general conclusions about the properties of this class of materials, known collectively as highly mis-matched alloys (HMA's).
Friday, 7 August
Assoc. Prof Mike Reid, (Physics and Astronomy Dept, University of Canterbury)
Lanthanide Optical Materials: Can we design a better light bulb? Materials containing lanthanide (rare earth) ions are used in a variety of optical applications, including lighting and display phosphors, scintillators, amplifiers, and lasers. I will discuss some of the physics of these materials that makes these applications possible. I will also touch on current and future research that we hope will provide the basic scientific understanding necessary to build new and improved devices.
Friday, 31st July
Jason Harris, Wolfram Research
Colloquium: The new era of Mathematica technology: Design principles of Mathematica, such as algorithmic automation, integrated symbolic computation, and its all-in-one architecture, will be discussed, with examples to illustrate Mathematica's benefits. This talk will introduce the Mathematica technical computing system and explain the design principles that have guided its development for over 20 years. Using simple examples from a range of science and engineering disciplines, the talk will also explain how these principles have accelerated the development of the system in recent years. Examples will include visualization, data analysis, symbolic computation, image processing, and application development. As well as showing Mathematica's use for free-form problem solving, the talk will discuss scalable deployment capabilities that enable the Wolfram Demonstrations Project and large applications, such as Wolfram|Alpha.
Friday, 24 July
Dr Philip Catton, (Philosophy Department, School of Humanities, University of Canterbury
What intelligence is: lessons from Newton”
Everyone lauds Newton as a scientific genius. Yet philosophers in the main possess an outrageous inclination to deprecate Newton as a philosopher. This is strange, considering (among other things) that the separation of science from philosophy was, though nascent, scarcely developed in Newton’s day. And Newton in any case led people, in actually very salutary ways, whether they knew it or not, to profoundly reconfigured intelligence about human intelligence itself. His intellectual leadership is vast in connections still thought of as philosophy today. In ways which few philosophers even to this day have possessed sufficient patience or acumen to recognise, Newton is philosophically penetrating in all the connections in which he has outrageously been characterised as dunce.
This talk therefore talks up Newton as a philosopher (in the contemporary sense of that word). Newton’s methodology of ‘deductions from phenomena’, his doctrines of space, time, force, substance and causality, his handling of idealisation and his understanding of truth, all are especially insightful, I maintain. Newton understood about chaos. He well grasped how all is interrelationship in the world. And in a profound extension of this to his reckoning of knowledge itself, Newton opposed Cartesian ‘first philosophy’. To this day, we would miss very fine opportunities to garner wisdom concerning ourselves, let alone our world, were we to fail, as so many philosophers do, to receive Newton as a pre-eminent philosopher.
An exception to drearily deprecating (and mistaken) philosophical reception of Newton is Kant’s. Like Newton, and because of him, Kant moves beyond Descartes, treating Descartes usefully as both inspiration and foil. Kant considered pervasive reasons why when thinkers reflect deeply about inquiry itself they are drawn into opposing camps: empiricists, rationalists; symbolically oriented, practically oriented; dedicated to analysis, dedicated to synthesis; logical, dialectical. Yet only by overstepping these oppositions can a thinker produce ultimate insight into what cognition is and how cognition is meet (to the extent that it is meet) for understanding the world.
Kant rightly credited Newton with clearly showing the way to overstep the oppositions in question. Before Newton, philosophers had asked whether science is possible. Yet Newton accomplished something so significant that after him there could be no doubt that science was actual. So after Newton, philosophers turned to asking how science is possible. Kant pursued this question with Newton his guide. Kant worked up inspiration from Newton into his transcendental, neither merely empiricist nor merely rationalist, philosophy. It is worth studying how this was, and why it profoundly progressed philosophy.
Descartes had proposed that the world is mechanical. Newton knew the world instead to be dynamical. The mind as Descartes proposed to think of it is capable of producing geometrical insights. Were the world merely mechanical, the mind would consequently be meet to comprehend the world. If the world is instead dynamical, then for such comprehension more than geometrical insight is required. Newton taught not only how to view the world as dynamical, but how to view the mind also as dynamical. In intellection as in the world all is interrelationship. Analysis is not finally fully tractable. There is no orderly philosophy, in which certain topics come first of all. These are Kantian insights that make their first clear appearance ever in Newton’s works.
More strongly than is ever acknowledged, Newton pressed people towards a different assessment of their own intelligence. Trust of general human intelligence was bound to grow; respect for one another’s reason became the practical imperative of an age. Political arrangements that are in various ways (and in whatever respects shakily) democratic were fated to blossom (to a degree), remarkably much because of Newton. Moreover, remarkably much because of Newton, mathematical reasoning would be ruminated about partly by thoroughly logical means. New power in logic would be discovered; computers would follow. Yet, Newton also pressed people to expect in all this, and in physics, an inevitable incompleteness. Substance (Newton taught us) is that of which no complete concept is possible. Analysis is originally and ineluctably unstable. Logic and computers demonstrably have limits. How far Newton propels us to these twentieth-century realisations, and how far Kant, by following Newton, had grasped their essence, is all moot perhaps, but in this talk I talk up the Newton connections.
Friday, 17 July
Friday, 10 July
Friday, 3 July
Dr Pauline Harris
Postdoctoral Fellow, School of Chemical and Physical Sciences,
Te Matariki, Puanga, Puaka, the revitalisation of Tatai Arorangi, Maori Astronomy and the Maori New Year.
The revitalisation of the Maori New Year has seen progress in the retention and usage of Tatai Arorangi (Maori astronomy). Most commonly Te Matariki, the Pleiades has been used to signify the Maori New Year, other iwi (tribes) from around the country use Puanga, or Rigel instead. The stars were not only important as sign posts for the navigators but were very important spiritually and as time indicators for ceremony, planting and cultivation. In this talk I introduce various aspects of traditional Maori star lore, from its use as a practical aid for navigation, to its use as a time indicator. I will discuss some various aspects of the importance of Matariki around the globe and will look at some of the commonalities of Astronomy from around the pacific.
Friday, 19 June
Dr Damian Carder, GNS Science, Lower Hutt
Nanotechnology at GNS Science: The nanotechnology group at GNS Science was established around a decade ago. Following a brief overview of the history and early activities of the group I will present details of our research over the past three years.
In particular I will discuss:- 1) An approach for creating nanostructured Germanium surfaces. This involves deposition of a thin layer of germanium under high vacuum using an ion beam sputtering system. The films are then annealed at temperatures between 400 -700 oC in an electron beam annealing system. Nanostructures are observed on the surface following the annealing process. Results of electron emission from these nanostructured ‘tips’ will be presented. 2) Recent advances in the demonstration of the application of silicon nanowhisker technology towards a field emission display device. And 3) Nanostructured surfaces in other materials (Fe and SnO).
Friday, 12 June
Dr John Greenhill, School of Mathematics and Physics, University of Tasmania
Optical astronomy in Tasmania The first significant astronomical observations by European settlers in Tasmania were made by two amateurs Abbott and Biggs. They published extensively in the latter part of the 19 th Century but it was nearly 100 years before astronomical research resumed. This arose from the establishment of an optical industry in Tasmania during World War II and the appointment of Theodore Dunham as a Professorial Fellow at the University of Tasmania. Dunham started Project Canopus to conduct spectroscopy in Australia and inspired the development of the Mt Canopus Observatory. A new observatory is now being built at Bisdee Tier in Southern Tasmania using one of Dunham's 50" mirror blanks.
In my talk I will discuss the history of astronomy in Tasmania, some of the achievements of the Mt Canopus Observatory and the new Bisdee Tier Observatory.
Friday, 5 June
Cheng-Yang Lee and Dimitri Schritt, PhD Students, Physics & Astronomy Dept, University of Canterbury
A theory of dark matter: The physics of Majorana and Elko spinors. Evidence for the existence of vast quantities of a novel form of non-luminous matter has been steadily mounting since the mid 1930s. It is now well established (baring major changes to the theory of general relativity) that this matter, commonly referred to as dark matter, is four to five times more plentiful in our universe than luminous matter, and yet in spite of intense efforts over the last seventy years, there is as yet no well established theory for its description.
We here present the colourful tale that led to the discovery of Elko, a particle candidate for dark matter proposed in 2005 by Ahluwalia and Grumiller, and give a general overview of recent research on Elko that is taking place here at Canterbury and abroad.
Friday, 29 May
Fulvio Melia University of Arizona)
Supermassive Black Holes In the past, they were recognized as the most destructive force in nature. Now, following a cascade of astonishing discoveries, supermassive black holes have undergone a dramatic shift in paradigm---these objects may have been critical to the formation of structure in the early universe, spawning bursts of star formation and planets. As many as 300 million of them may now be lurking through the vast expanses of the observable cosmos, but how did many of them form only 800 million years after the big bang? We will examine the exciting observations that have brought us to this point, and discuss the impact these are having on our understanding of structure in the universe.
Friday, 22 May
Dr Peter Wilson, Honorary Fellow, Physics Department, University of Otago & Director, Otago Osmometers Ltd
Polar fish to methane hydrates - the stochastic nature of heterogeneous nucleation - Non-equilibrium systems tend to reach equilibrium eventually, but a unified theory characterizing this evolution in time is still lacking, especially for the liquid to solid transition. The statistics of liquid-to-crystal nucleation are measured rigorously by using a recently developed automated lag-time apparatus (ALTA). ALTA repeatedly supercools one sample until the onset of nucleation then heats the sample to ensure melting of all residual ice crystals prior to the next run. This cycle is repeated on the same sample and the technique provides an advantage over trying to prepare and monitor say 300 individual identical samples.
Analysis of the data, coupled with a second kind of experiment, shows that the statistics of heterogeneous nucleation are consistent with a first-order kinetic mechanism over a wide range of supercooling temperatures. The limitations of classical nucleation theory are exhibited.
Our analysis unifies many related experiments in biology, physics, chemistry, and chemical engineering. I will discuss examples ranging from Antarctic fish “antifreeze” proteins to methane hydrates formed at10 MPa.
Friday, 15 MayDr Andreas Gross Postdoctoral Fellow, Department of Physics and Astronomy, University of Canterbury
Search for neutrinos of astrophysical origin with IceCube
The search for neutrinos of astrophysical origin is among the primary goals of the IceCube neutrino telescope. Source candidates include galactic objects like supernova remnants (SNRs) and X-ray binaries as well as extragalactic objects like Active Galactic Nuclei (AGN) and Gamma-Ray Bursts (GRBs).While IceCube is an all-flavour detector, the event signatures of the three flavours differ significantly from track-like muon neutrino induced events to rather spherical cascades induced by electron neutrinos. The complimentarity of these different detection channels with respect to the scientific goals of IceCube will be discussed in this talk.
Friday, 8 May
Dr David Wiltshire Senior Lecturer, Physics and Astronomy Dept
Cosmological Equivalence Principle
Through a series of thought experiments, I will tackle foundational questions which follow naturally from the questions Einstein asked when he first thought about the Equivalence Principle 100 years ago. I argue that Einstein overlooked an important aspect of the relativity of time in never quite realizing his quest to embody Mach's principle in his theory of gravity. As a step towards that goal, I broaden the Strong Equivalence Principle to a new principle of physics, the Cosmological Equivalence Principle, to account for the role of the evolving average regional density of the universe in the synchronization of clocks and the relative calibration of inertial frames. I apply the principle quantitatively to deduce the relative deceleration of observers in expanding regions of different density, which empirically accounts for the phenomenon we call "dark energy". This will be a conceptual talk, with some historical context; technical baggage will be kept to a minimum.
Friday 1 MayRueben Mendelsberg, PhD Student, Physics & Astronomy Dept,
University of Canterbury
A summer in San Jose: Phase change alloys at IBM Almaden
IBM Almaden Research Center, in the heart of Silicon Valley in San Jose, California is home to 400 researchers from nearly all parts of the globe. Last August I was one of two lucky New Zealand students to work amongst these world class engineers, chemists, biologists, and physicists, as part of the inaugural MacDiarmid Institute IBM PhD Studentship. I'm very pleased to see that it has become an ongoing, annual placement because it is a chance for New Zealand students to get hands on experience in a thorough, yet fast paced research environment.
My work was investigation of GeSb alloys which can be quickly and reversibly switched between a metastable amorphous phase and a stable crystalline phase. The large difference in electrical resistivity between the two phases can be used to store data, the electrical analogue to the rewriteable DVD. No moving parts, non-volatility, and size scalability below the theoretical limit for flash memory may put phase change memory in the front of the next generation of memory technology. Working at IBM Almaden was an experience I'm lucky to have had and one that I'll never forget. In this talk I will talk about the people I met, the things I did and saw, and the joys and pains of comparing computer simulations to experimental observations.
Thursday 23 April (note different day)Dr Matt Visser
School of Mathematics, Statistics, and Computer Science, Victoria University of Wellington
Lorentz symmetry breaking as a quantum field theory regulator Perturbative expansions of relativistic quantum field theories typically contain ultraviolet divergences requiring regularization and renormalization. Many different regularization techniques have been developed over the years, but most regularizations require severe mutilation of the logical foundations of the theory. In contrast, breaking Lorentz invariance, while it is certainly a radical step, at least does not damage the logical foundations of the theory. We shall explore the features of a Lorentz symmetry breaking regulator in a simple polynomial scalar field theory, and discuss its implications. We shall quantify just "how much" Lorentz symmetry breaking is required to fully regulate the theory and render it finite. This scalar field theory provides a simple way of understanding many of the key features of Horava's recent article [arXiv:0901.3775 [hep-th]] on 3+1 dimensional quantum gravity. See: arXiv:0902.0590v2 [hep-th]
Professor Doug Hamilton
Erskine Visitor from the Dept of Astronomy, University of Maryland
Non-Gravitational Forces in Jupiter's Dusty Rings Saturn's resplendent rings, discovered by Galileo in 1610 are more than a billion times more massive than Jupiter's, seen for the first time by the Voyager spacecraft in 1980. The former are now known to be composed of icy particles ranging in size up to several tens of meters while the latter are dominated by micron-sized rocky dust. The reason for these striking discrepancies are still not understood, but because the systems differ so greatly, they highlight very different limits of ring physics. Saturn's rings are dominated by collisions while, in contrast, Jupiter's are sculpted by non-gravitational forces. In this talk I will discuss how the interplay of electromagnetic forces and sunlight determine the appearance of Jupiter's dusty rings.
Wednesday (Extra Seminar) 1 April, 3:00pmElizabeth Winstanley
University of Sheffield ,
UKBlack holes at the LHC
Brane world models in string theory suggest that our universe is a slice, or "brane", of a higher-dimensional space-time. One consequence of these models is that the energy scale of quantum gravity may be many orders of magnitude lower than previously thought, and may be as low as a few TeV. If this is the case, copious numbers of black holes will be formed by collisions at the LHC. In this talk we will review aspects of the formation and subsequent evaporation of these mini-black holes. For simplicity, we will consider only the simplest brane world models, where the extra space-time dimensions are flat. We focus particularly on the emission of particles by the black hole, both particles visible within the detectors and particles which contribute to the missing energy.
27 March, 11:00 a.m.
Professor James E. Morris Department of Electrical & Computer Engineering Portland State University, Portland OR 97207-0751, USA Nanopackaging: Nanotechnologies in Microelectronics Packaging Nanotechnologies offer a variety of materials options for reliability improvements in microelectronics packaging, primarily in the applications of nanoparticle nanocomposites, or in the exploitation of the superior properties of carbon nanotubes. Nanocomposite materials are studied for resistors, high-k dielectrics, electrically conductive adhesives, conductive “inks,” underfill fillers, and solder enhancements, while CNTs may also find thermal, interconnect, and shielding applications. The talk will focus on these technologies, following a brief “What is packaging?” introduction, with a mention of the packaging reliability issues for post- CMOS nanoelectronics technologies.
BIOGRAPHY: Jim is an ECE Professor at Portland State University, Oregon, and Professor Emeritus at SUNY-Binghamton, having served as Department Chair at both, and is an IEEE Fellow. He has B.Sc. and M.Sc. degrees in Physics from the University of Auckland, NZ, and a Ph.D. in EE from the University of Saskatchewan, Canada, and was the first Director of Binghamton’s Institute for Research in Electronics Packaging. Jim has served the IEEE CPMT Society as Treasurer (1991-1997,) BoG member (1996-1998), VP for Conferences (1998-2003,) Distinguished Lecturer (2000- ,) CPT-Transactions Associate-Editor (1998- ,) IEEE Nanotechnology Council representative (2007- ,) etc., and won the 2005 CPMT David Feldman Outstanding Contribution Award. He has edited four books on electronics packaging, including one published last year on Nanopackaging, established the Nanotechnology Council Nanopackaging TC, and contributes to IEEE Nanotechnology magazine. He was General Conference Chair of Adhesives in Electronics (1998,) Advanced Packaging Materials (2001,) and Polytronic (2004.) His research is currently focused on ECAs, nanoelectronics, and nanoelectronics packaging. He is actively involved in international engineering education, was founding chair of the IEEE Education Society’s Oregon Chapter, and has won Nokia-Fulbright (Helsinki) and Erskine Fellowships in 2009, as part of a sabbatical. Jim is a Kiwi, born in Christchurch, and lectured in Physics at Victoria University of Wellington through the 1970’s, where he developed microprocessor automotive engine controls for fuel economy.
Friday 20 March, 11:00am
Gil Jannes, Astrophysics Institute of Andalusia, Granada, Spain
Sensitivity of Hawking radiation to superluminal dispersion relations The Hawking radiation process due to collapsing conﬁgurations is analysed in the presence of superluminal modiﬁcations of the dispersion relation. With such superluminal dispersion relations, the horizon e ﬀ ectively becomes a frequency-dependent concept. In particular, at every moment of the collapse, there is a critical frequency above which no horizon is experienced. As a consequence, the late-time radiation su ﬀ ers strong modiﬁcations, both quantitative and qualitative, compared to the standard Hawking picture. Even if the critical frequency is well above the Planck scale, important modiﬁcations still show up.
Friday 13 March, 11:00amStephanie McLaughlin
Faculty Research Assistant Astronomy Department, University of Maryland Deep Impact: Excavating Comet Tempel 1
On 4 July 2005, Deep Impact delivered 19 gigajoules of kinetic energy at an oblique angle to the surface of comet 9P/Tempel 1, excavating a crater and showing us the insides of a comet for the first time. Observations acquired by instruments on-board the spacecraft during the approach, encounter, and lookback phases of the mission have yielded a broad spectrum of knowledge about this Jupiter-family comet. This talk will present some aspects of our evolving understanding of comet Tempel 1.
Friday 6 March , 11:00amManfred Simon, University of Siegen , Germany
The Pamela Mission: A Space Experiment to measure energetic Matter and Antimatter from Space
The Pamela Experiment has been in orbit since June 2006 and we have been receiving continuous scientific data since that time.
The instrument is designed to measure the energetic cosmic ray particles and antiparticles from space over a large energy regime from 100 MeV to almost 1TeV. The main experimental components of the instrument are: A magnetic spectrometer, with a permanent magnet, a time of flight system and an imaging calorimeter. These detectors in combination provide a high level of particle identification. The instrument precisely measures the charge, the charge sign and the energy of the incoming particles and the long observation time of currently more than 2 years provides an unprecedented statistical precision.
Pamela not only measures the antiprotons and positrons in an unexplored energy regime, the Pamela measurements in general will improve the cosmic ray observation in many aspects. This applies to the galactic cosmic rays as well as to the solar particles.
The talk will shortly explain the instrument and will then focus on first results with a specific emphasis on the recently published positron and antiproton data.
Friday 27 February, 11:00am
School of Chemistry and Physics, University of Adelaide.
Ultra-High Energy Cosmic Rays and the Pierre Auger Observatory
When dealing with ultra-high energy cosmic rays, a bigger experiment is almost invariably better; the flux of the highest energy cosmic rays at earth is vanishingly small – just 1 per square kilometer per year above 10 EeV, so a large collecting area is essential. The Pierre Auger Observatory was designed for the task of detecting these particles. It is a “hybrid detector” consisting of two complementary components - a surface array of water Cherenkov tanks covering 3000 km^2 which sample cosmic ray air shower particles at ground level, and an overlooking set of 24 fluorescence telescopes which observe the nitrogen fluorescence as those air showers pass through the atmosphere. In combination, these two components enable the robust collection of unprecedented statistics.
In this talk I will outline the traditional “big three” unknowns with regard to ultra-high energy cosmic rays: what they're composed of, where they come from, and just how energetic they can get. I will also talk about how the Pierre Auger Observatory is addressing each of them.
Friday 20 February, 11:00am
Antonio de Ugarte Postigo
Current status of gamma-ray burst research This talk will present an overview of the status of the field of gamma-ray burst (GRB) research. Beginning with a historical view, from the discovery of the first GRB in the late 60's through the first afterglows in the 90's and to the current era of great advances with Swift and Fermi satellites devoted to GRB research. We will then discuss the observational characteristics of the different types of GRBs and the physics that is explaining their peculiarities. Finally we will present the latest discoveries, including the brightest GRB to date, which was bright enough to be visible with the unaided eye or the furthermost GRB, discovered a few months ago, with a redshift of z=6.7. I will emphasise on the unique observational needs for the study of GRBs, including the need for dedicated robotic telescopes.
Friday, 13 February, 2:00pm (2nd Seminar)
Silke Weinfurtner ( University of British Columbia)
Signature change events: A challenge for quantum gravity?
Within the framework of either Euclidean quantum gravity or canonical general relativity, the ignature of the manifold is a priori unconstrained. Furthermore, recent developments in the emergent spacetime programme have led to a physically feasible implementation of signature change events. This suggests that it is time to revisit the controversial topic of signature change in general relativity.
From the viewpoint of quantum gravity phenomenology, we discuss possible consequences of an effective Lorentz symmetry breaking scale.
Friday, 13 February, 11:00am (1st Seminar)
Thomas Sotiriou University of Maryland
The multiple deaths of Palatini f(R) gravity.
Modified gravity theories have received increased attention lately due to combined motivation coming from high-energy physics, cosmology and astrophysics. Difficult as it may be to propose a viable alternative to General Relativity, one can think of some of the alternative theories under scrutiny as toy theories, the study of which can help us explore the limitations of beyond-Einstein gravity. This will be demonstrated - after a brief introduction to modified gravity has been given - by using Palatini f(R) gravity and the various ways to rule it out as a viable gravity theory as an example.
Thursday, 5 February, 2:00pm
Dr Adam Micolich
Senior Lecturer, School of Physics, University of New South Wales, Sydney
Physics postcards from Sydney: hole quantum wires, organic crystals and ion-implanted polymers
I will give a brief overview of some of the interesting physics projects currently being undertaken by the Quantum Electronic Devices group at the University of New South Wales in Sydney, Australia. This will include snapshots of three different projects: Investigations of the spin-properties of GaAs quantum wires where holes rather than electrons are used as the charge carrier, the study of field-effect transistors based on semiconducting organic molecular crystals, and the development of superconducting plastic films by using an ion-beam to mix metal into the surface of polymer substrates.
Tuesday 27 January, 11:00am Special Seminar
New Zealand PhD student, Imperial College, London
Causal Set Theory
Is spacetime a discrete or continuous structure? I will briefly review causal set theory, a Lorentz invariant discrete approach to quantum gravity, and then discuss how discreteness could affect particle behaviour. Particles propagating in a fundamentally discrete spacetime will not follow the smooth geodesics predicted by GR. Motivated by causal set theory we can develop phenomenological models for such particles. On macroscopic scales the particles will undergo a diffusion in momentum. Comparison with observation allows us to place tight constraints on the free parameters in the model.