Colloquia

Colloquia

Our colloquia are held in E7B T2 on Tuesdays beginning at 1:00 pm. Our departmental colloquium series includes speakers from across all physics sub-disciplines, and is intended to be delivered at the senior undergraduate to graduate level, engaging an audience of researchers in areas as diverse as biophysics and astronomy. If arriving from off campus, we are accessible by train – just outside Macquarie Uni station – and paid parking is also available (from $10/hr). For up-to-date announcements about upcoming colloquia, please subscribe to the sci.physics mailing list, our RSS feed, and/or our iCalendar. Information regarding previous colloquia may be found in the left hand navigation bar.

Our Next Talk

30/05/17 – Is There Anything I Can Do To Improve Diversity Other Than Retire?

Geoff Clayton

Louisiana State University
Things are changing so fast that it makes an old white guy's head swim. Native Hawaiian's delay telescope construction, a well-known astronomer resigns after multiple claims of sexual harassment, and we are uncertain about what pronouns and bathrooms to use. The admirable goal of a more diverse workplace, where everyone feels included and valued, requires better communication and understanding that each person is having a different experience in the same workplace. All of us need to become more aware of our own unconscious biases, and the roles of white and male privilege. I plan to discuss where we are now, and where we go from here.

Geoff Clayton

Semester 1 Talks

28/02/17 – How the Milky Way Shaped Itself

Hans-Walter Rix

Max Planck Institute for Astronomy
The Milky Way is the only galaxy we can see star-by-star in 3D. This unique wealth of information makes our galaxy an ideal model organism to test our overall concepts of galaxy formation and evolution. Over the last years, new spectroscopic surveys have allowed us to measure the detailed abundances (=birth-material composition) and ages of stars throughout the Galactic disk. I will aim at providing (current) answers to these questions, and sketch out briefly my view of what is yet to come with the unprecedented data from the Gaia satellite mission.

Hans-Walter Rix

28/03/17 – Magnetic Toys in the Sky

Yuri Levin

Monash University
In terrestrial conditions, magnetic fields usually play second fiddle to matter. However, in space magnetic fields can play a decisive role in dynamics of many astrophysical objects. In my talk I will describe two interesting magnetic phenomena that do not have counterparts in terrestrial conditions: 1. Magnetically driven hurricane-like deflagration fronts that are explosively consuming oceans on rapidly spinning neutron stars, and 2. Avalanches of magnetically-induced thermoplastic failures in magnetar crusts that my be connected to the observed activity of magnetars.

Yuri Levin

04/04/17 – THz Hollow-Core Waveguides with Metamaterial Cladding

Shaghik Atakaramians

University of Sydney
An essential component in developing compact terahertz devices are waveguides. Among several waveguide solutions proposed for guiding THz radiation, hollow-core waveguides are one of the best options due to the low losses of THz waves in air. However, these waveguides usually have diameters on the order of several wavelengths and consequently are rigid, multimode pipes for guiding THz radiation rather than flexible fibres. The emergence of metamaterials opens a new avenue to overcome some of the limitations of hollow-core THz waveguides, by providing new guidance mechanisms and extreme birefringence that guide a single polarization. In this presentation, I will discuss our recent work—theoretical, numerical, and experimental demonstrations—on hollow core waveguides with hyperbolic metamaterial cladding. In the THz spectrum such waveguides offer a unique combination of being mechanically flexible, with low optical loss and large single-mode bandwidth.

Shaghik Atakaramians

02/05/17 – Galaxy Formation and Evolution in 3D

Lisa Kewley

Australian National University
Tracing matter and chemical elements in the Universe is critical for understanding the formation of the first galaxies, the formation and growth of supermassive black holes, and ultimately the evolution of galaxies like our Milky Way. Throughout the history of the universe, large-scale gas flows have moulded the arms of spiral galaxies, formed the bulges of the most massive galaxies in the universe, fed supermassive black holes in the centers of galaxies, fueled generation upon generation of new stars, and enriched the intergalactic medium with metals. The physics and impact of these processes can now be traced through new efficient, wide-field 3D integral field spectrographs. We use multi-object integral field spectroscopy to build the largest local sample of galaxies with wide 3-dimensional imaging spectroscopy. We combine our local results with insights into the early universe probed through gravitational lensing and adaptive optics. I will present the latest results from our large local and high-redshift 3D surveys to understand the relationship between gas inflows, galactic-scale outflows, star-formation, chemical enrichment, and active galactic nuclei in galaxies. I will finish by discussing how this field will be transformed in the upcoming era of the James Webb Space Telescope and ground-based Extremely Large Telescopes.

Lisa Kewley

16/05/17 – A Winding Road with a Broad Impact: Towards Graphene on Silicon

Francesca Iacopi

University of Technology Sydney
Graphene has enormous potential for integrated devices, as it can enable the ultimate system miniaturization through the combination of many of its outstanding functionalities—from electronics to photonics, sensing and energy storage—all within a small and energy–efficient package. However, in order to realize this promise, first a graphene of acceptable quality needs to be synthesized consistently over large areas, and preferably directly on a substrate like silicon. Interestingly, despite extensive research efforts over the last decade, the direct synthesis of graphene on silicon has been lagging behind. We have pioneered an avenue to fill this fundamental gap. As no novel methodologies come without complexities, we review the associated challenges and the broader perspectives.

Francesca Iacopi

23/05/17 – Engineering Defects In Diamond

Mark Newton

University of Warwick
Defects in diamond have great potential for use as quantum sensors and qubits. Full exploitation of their optical and spin properties necessitates that we control their position, orientation and environment to optimise all of the desirable properties simultaneously. In this talk I will review our understanding of the production of intrinsic defect complexes and present new data on the production of preferentially orientated defect complexes by electron irradiation and/or annealing whilst the sample is subjected to a large uniaxial stress. Near 100 % preferential orientation can be achieved for a number of different defects. Furthermore, recent results will be presented where uniaxial stress has been used in-situ to investigate both the reorientation and the spin relaxation properties of the single substitutional nitrogen centre in diamond. Finally, I will discuss some of our experiments on all optical spin polarisation using defects other than the nitrogen vacancy.

Mark Newton
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