The School of Physics at UNSW offers guided expertise to early career physicists throughout their PhDs. Across a spectrum of specialised fields, these young researchers are expected to undertake in depth studies and conduct original analysis. Part of the process of gaining one’s PhD is garnering the ability to present in a public arena on a unique scientific topic. As our PhD students near graduation, presentations are organised within the school so that fellow PhDs, scientists and academics can listen and make comment.
These are the Physics PhD Presentations for Nov / Dec 2021:
Friday 19 November 10am
Shannon Melrose - Early Career Astrophysicist
Understanding star formation through an N-PDF analysis of the VMR-C
Star formation is crucial to contemporary astrophysics, with the formation and evolution of stars driving the evolution of galaxies at all epochs. While stars are well known to form in the cold, dense cores of molecular clouds, a universal theory of star formation remains elusive and high mass star formation in particular is poorly understood. Considering the characteristic temperatures and densities of molecular clouds, a purely gravitational model of star formation would give a star formation rate 10 to 100 times greater than observed.
In order to resolve such inefficient star formation, Shannon’s PhD work seeks to better understand the roles and relative contributions of gravity, turbulence, magnetic fields, and stellar feedback in governing the gas dynamics of star formation environments. Using observational data from the Australia Telescope Compact Array, he applies column density probability distribution function analyses to separate the turbulence dominated and gravitationally bound components of the interstellar medium. Shannon is co-supervised by CSIRO Space and Astronomy.
Friday 26 November 10am
Lara Gillan - Early Career Condensed Matter Physicist
Understanding the role of carrier and spin dynamics in emerging photovoltaics
Lara’s PhD work examines the properties of emerging photovoltaics which effect the power output of these devices. With excellent capacity for cost-effective power generation, emerging solar cell technologies based on organic and perovskite materials are compelling alternatives to conventional semiconductor technologies currently dominating the commercial market. While there has been much work investigating novel materials and architectures to improve the performance of these devices, a sufficient understanding of the physics which dictate their operation remains yet to be achieved.
In order to optimise emerging solar cell technologies, it is crucial to understand the processes intrinsic to charge carrier generation and the material properties which determine the evolution of these states. Here we employ a combination of electron spin resonance spectroscopies and time resolved microwave conductivity measurements to unravel the dynamics of photogenerated species in both thin ﬁlms and operating photovoltaic devices.
These studies contribute to more informed understandings of how these emerging photovoltaic materials operate, which will help to pave the way for improvements in material and device design.
Friday 3 December 10am
Joe Chen - Early Career Astrophysicist
Chasing neutrinos in the sky
Joe’s PhD provides insight into effects neutrino physics have on galaxy clustering statistics. Past and current astrophysical surveys of the large-scale galaxy and matter distribution of the universe have yielded a plethora of information about its energy content, geometry, and initial conditions. Important quantities such as the dark matter and dark energy energy densities have been measured to percent precision. The ESA Euclid mission and Large Synoptic Survey Telescope are expected to improve on these measurements by at least fivefold in accuracy, and constraint even the most elusive parameters like the neutrino mass to 0.05 eV levels. To enable these (expensive) instruments to realise their full potential, however, scientists must first be able to predict from theory the relevant observables to the same precision, and pave the way for the meaningful interpretation of forthcoming observational data.
In his thesis, Joe contributes to this theoretical effort by providing accurate and efficient predictions of large-scale structure statistics in the mildly-nonlinear to nonlinear regime using a combination of perturbation theory and numerical n-body simulations.