Vice Chancellor Visits School
The School of Physics was proud to host Professor Ian Jacobs, just eight days into his tenure as Vice Chancellor of UNSW Australia. Ours was the first School visited as he begins his grassroots campaign to systematically visit all 51 schools across campus. Professor Jacobs outlined his vision for UNSW and the consultative processes he has established to develop strategies to achieve that vision. While here, he met with staff and students, toured our laboratory spaces, and enthusiastically attended short talks on some of the school's research highlights. Outlines of these are listed below.
Prof. Chris Tinney: Exoplanetary Science at UNSW
The Exoplanetary Science at UNSW research group based within the School of Physics is indisputably Australia's leading research group in the search for, and study of, planets orbiting other stars. Over more than a decade its members have identified more than 45 planets orbiting other stars, with recent highlights including the discovery of a habitable-sone planet orbiting the low-mass stars GJ832, just 16 light years from our Sun.
The next decade is set to be an exciting one for this field, with NASA's Transiting Exoplanet Survey Satellite (TESS) launching in 2017 and identifying thousands of new transiting exoplanets orbiting bright southern stars. To position Australia to take a leading role in exploiting this flood of new planets, the Exoplanetary Science at UNSW team are building the new $1.6m Veloce spectrograph for the Anglo-Australian Telescope, as well as leading the FunnelWeb spectroscopic survey of more than 3 million of the brightest southern stars. Together this will mean that when TESS finds a new planet, FunnelWeb data will tell Australian scientists what the host star's properties are in detail, while Veloce will put us in a position to rapidly carry out follow-up observations to determine that planet's mass and density, which in turn tells us whether TESS' planets are rocky (like the Earth) or icy (like Neptune).
[Photo: Artists conception of the GJ832 system. Credit: PHL @ UPR Arecibo, NASA Hubble, Stellarium]
Dr. Julian Berengut: Do the constants of nature change over space and time?
My research tests whether the laws of physics are fixed everywhere in the Universe, or whether they change over space or time. The research centres on the ‘Goldilocks’ riddle: Why is the Universe ‘just right’ for life to exist? If the laws of physics were only slightly different, human beings would not be able to exist to ask the question. The question therefore makes life itself seem quite unlikely. We are testing one alternative: if the laws of physics are different in different parts of the Universe, then it becomes likely that some ‘part’ of the Universe has the right conditions for life to exist, and that’s where we appear.
Our team at UNSW, headed by Prof. John Webb, recently found hints that the fine-structure constant (a dimensionless constant that involves the speed of light) takes on different values across the Universe. It appears that there is a spatial gradient in values of this constant across cosmological distances. The team received the Eureka Prize for Scientific Research in 2012.
More recently, I have been working on very precise atomic clocks that could confirm the spatial gradient seen by astronomers. The clocks we have designed are predicted to be 100x better than current atomic clocks, and could revolutionise fields such as navigation, mining, water management, and climatology.
[Photo: Infographic explaining measurement of cosmological alpha variation]
Prof. Alex Hamilton: More spin for your buck!
It has been know for over 100 years that electricity in semiconductors is carried by negatively charged electrons and positively charged holes. However while the properties of electrons are very well understood, the understanding of holes (particularly when confined to move in nanostructures) is much less well understood. A common theme of our work is to understand the properties of valence band holes in semiconductor nanostructures.
It is only in the past few years that we are beginning to understand just how different holes are from electrons. For example, whereas electrons have a well defined dipole moment that couples their spin to an externally applied magnetic field, holes also have quadrupole and octopole moments that have no equivalent in electrons. These unique spin properties have led to proposals for novel spin based hole transistors, that could run much faster and with lower power than conventional devices that rely on the charge of electrons, as well as new types of quantum bits for quantum information applications. A key goal of our work is to provide the underpinning knowledge of the spin properties of holes, so that they can be fully exploited for future spin-based electronics applications.
Prof. Joe Wolfe: The Acoustics Lab
This small team in the School of Physics works in acoustic measurement technology, the voice and music acoustics. The group uses a unique technique to measure the acoustical response of the human vocal tract, during speech, singing or playing musical wind instruments. Looking at the voice, the team has measured the resonant frequencies, bandwidths and losses of the vocal tract in speech and analysed the strategies used by singers, particularly at high pitch. The team also researches the interactions between musical wind instruments and their players, discovering how embouchure parameters and mouth shape are controlled and coordinated by expert players. This research, which is helping understand how good players make good music, is published in high profile scientific journals, but it is also made accessible to singers, musicians, students and teachers via a large and popular web site.
[Photo: While Francesco Celata plays some Gershwin, sensors inside the clarinet mouthpiece send hundreds of frequencies into his mouth to measure how his vocal tract is involved during playing.]