Taste of research

We investigate new materials and quantum devices, with a focus on systems that may have applications in a future quantum computer made from spins, superconductors or topological systems. Experimental projects may involve activities ranging from device design and fabrication in a clean room environment, electromagnetic simulation, cryogenic measurement in dilution refrigerators, as well as developing control software for qubit measurement.

Quantum computing

Quantum computation focuses on using quantum bits to encode information. Unlike classical bits, which can be either 0 or 1, quantum bits exploit the superposition principle and can be in any combination of 0 and 1, which can make computation considerably faster and open new avenues that are inaccessible with classical bits. The two key problems facing the community at present are increasing the lifetimes of quantum bits (coherence), which determines how long quantum information can be stored, and devising ways to couple two or more bits so that complex operations can be performed in practice (entanglement). The research projects will focus on these two phenomena, devising novel strategies to beat decoherence mechanisms and to control interactions between quantum bits.

Topological quantum matter

In recent years a large number of physical phenomena have been ascribed to topological mechanisms, in which the curvature of the eigenspace of the system plays a vital role in determining the robust quantisation of response functions. These phenomena are so widespread nowadays that the 2016 Nobel Prize was awarded to three scientists who revealed their topological nature, and the Australian Research Council has established the Centre of Excellence in Future Low-Energy Electronics Technologies to investigate topological materials and effects. The research projects will focus on establishing the role of topological terms in the response functions of a series of newly discovered materials, including topological insulators, Weyl semimetals, and transition metal dichalcogenides.

Research interests of our group include:

• Atomic and nuclear theory and high precision atomic calculations
• Properties of superheavy elements
•  Atomic and nuclear clocks
• Violation of the fundamental symmetries and tests of Grand Unification theories
• Dark matter models and search for dark matter
• Search for cosmological variation of fundamental constants in an evolving Universe
• Quantum chaos and statistical theory of small systems
• Quantum effects in strong gravitational field and black holes

My group’s research revolves around the physics of the early Universe and in particular what observations can tell us about the Universe’s history, composition and origin. Depending on students' prior knowledge and interest, I offer projects on topics such as cosmic inflation, Big Bang Nucleosynthesis, the cosmic microwave background, the formation of the Universe’s large scale structure, or machine learning for data analysis.

I am offering research projects in experimental condensed matter physics, studying the electronic properties of advanced quantum devices and topological materials (https://www.physics.unsw.edu.au/qed). Potential projects include

• Spin-3/2 qubits in silicon quantum dots
  Electrons are spin ½ particles whereas positively charged holes are spin-3/2, and make very fast quantum bits. We study extremely fast qubits in silicon quantum devices.
• Measuring the quantum Hall effect in two-dimensional systems

The quantum Hall effect has been the subject of 3 separate Nobel prizes. Here you will measure the quantum Hall effect in 2D systems at temperatures below 2 Kelvin and magnetic fields up to 9 Tesla.

• Studying quantum electrical transport in one-dimensional nanowires
• Putting the flow back into electrical currents - hydrodynamics of electrons in quantum devices

We often talk of "electrical currents"; here we are exploring the viscous nature of the electrical fluid that flows in transistors.

• Making and measuring atomically thin transistors using graphene and the "sticky tape" fabrication approach

These projects will be rather "hands-on", with students working with researchers in our group to perform experiments themselves, taking their own data, and in some cases handling liquid cryogens and helium refrigerators.

My research group works in the area of Galactic archaeology, using the present-day properties of the Milky Way to investigate its history and evolution. I am offering projects studying the chemical compositions and orbits of stars in our galaxy, including:

• Identifying stars that have been captured from other galaxies
• Data mining in large survey data sets to find stars with anomalous compositions
• Determining the orbits and initial properties of stellar streams in the Galactic halo

These projects all involve python programming, and no prior programming experience is required.

Coherent spin manipulation and control of organic electronics

Coherent quantum effects are usually associated with extremely low temperature, making widespread technological applications difficult. Projects in the Centre for Exciton Science will investigate organic semiconductors, a class of material which exhibit quantum coherence in devices operating at room temperature. Projects may involve activities ranging from device design and fabrication in an oxygen free environment, to developing experimental systems for room temperature coherent control of spin states. The goal is to perform electrically or optically detected spin resonance experiments on a range of organic molecules, thereby increasing our understanding of spin coherence in these materials. Students interested in this area are encouraged to contact Dane to design a project that fits their interest and skills.

Spin based spectroscopy of light harvesting and modifying materials

The interaction of light with molecules leads to the formation of excitons. Projects in the Centre for Exciton Science will investigate molecular and nanoscale systems that allow engineering of the light spectrum via a range of spin dependent exciton interactions. Projects may involve activities ranging from device design and fabrication in an oxygen free environment, to developing experimental systems for optically exciting and measuring the influence of spin in these novel materials. The goal is to increase our understanding of electronic processes which can improve the efficient conversion of light into charge, and therefore improve energy generation in photovoltaic materials. Students interested in this area are encouraged to contact Dane to design a project that fits their interest and skills.

Biological-microscopy-capable nanoelectronic devices
Advanced biosensors featuring nanoscale electronic devices have been the subject of intense research interest for many years. For the most part, such devices have been developed on traditional Si/SiO2 substrates for use as purely electronic sensors without any capacity for simultaneous optical microscopy. In parallel, biological microscopy has made major leaps forward both in resolution and the simplicity and reduced cost of the infrastructure, for example, 3D printed high-resolution microscopes using cellphone cameras are a thriving development frontier. Biological microscopy methods use ultrathin glass, a highly unconventional substrate for nanoscale electronic devices. This 'substrate mismatch' has led to nanoscale electronic biosensors and advanced biological microscopy evolving in isolation despite an interest in similar biological targets and questions. We are currently working on nanoscale electronic devices designed such that biological microscopy can be performed at the device simultaneously with the electrical measurements. This work involves collaborations with University of Tokyo in Japan, Lund University in Sweden, Swansea University in Wales, Victoria University of Wellington in New Zealand, TU Dresden in Germany and other groups at UNSW.

My research group studies exoplanets--worlds orbiting stars other than our own sun--and the physics of their host stars. To answer these questions, we use data from the NASA Kepler and TESS missions, two surveys that together have obtained long-term observations of the brightnesses of millions of stars. These data can be used to detect the presence of planetary systems as well as understand stellar activity like starspots, flares, and magnetic cycles. Students involved in these projects will have the opportunity to work with large data sets and explore statistical data analysis methods to study planets, stars, and interactions between the two.

My group’s research involves using the latest theoretical and computational techniques to describe living matter--- from cells to tissues to organisms.  The overarching goal is to extend the remit of classical physics, and push biology and medical science towards working hand-in-glove with theory and computation, much like present day engineering.  We are based in the Lowy Centre for Cancer Research and work alongside experimental partners who operate at the cutting edge of modern biology and microscopy.  Students involved in this work will gain exposure to subjects such as genetics, molecular biology, mechanosensation, virology, and cancer research, as well as theory and computer simulation / numerics.

My research involves the theory and simulation of quantum materials and devices. My group has developed a number of computational tools and techniques to model and simulate physical mechanisms governing qubit operations, lifetimes, and coherence. With these methods, we collaborate with experimental groups to understand measurements, and to design and optimize quantum hardware. Our specialization is on silicon qubits hosted in dopants and quantum dots, but we also work on III-V material qubits. We also work on nano-electronic devices, including novel transistors beyond Moore's Law. Our goal is to utilize novel properties of emerging materials such as 2D and topological materials to design novel transistors and optical devices.

Manipulating nanoparticles with holographic optical tweezers

Optical tweezers use the momentum carrying properties of light to confine and manipulate nanometre- and micrometre-scaled objects at the focus of a high magnification microscope objective lens. Combining optical tweezers with holographic techniques allows for the direct manipulation of multiple trapped objects in three dimensions. In this project you will create digital holograms for the purpose of manipulating nanoparticles in amusing ways. Along the way you will (hopefully) learn about optical tweezers, adaptive optics, Fourier optics, holography and nanoparticle physics.

My group works on coupling qubits in a robust manner from the atomic nano-meter length scale to macroscopic coupling via photons. On the atomic scale we optimise the coupling between donor atoms while taking the complex nature of their charge density in silicon into account. To achieve macroscopic coupling we engineer electric-dipole coupling to spin qubits. This enables direct qubit-qubit coupling at the 100nm length scale and the coupling to microwave resonators that allows for chip scale coupling. For the optical interface to spin qubits we establish long distance coupling based on rare-earth ions in silicon with compact optics and integrated single-photon detectors in collaboration with ANU, Griffith, RMIT, and UNSW Canberra.

I am a theoretical physicist working on astroparticle physics and physics beyond the Standard Model of particle physics. My research focuses on neutrino and flavour physics. I am also interested in light sub-GeV physics. I am offering undergraduate research projects on neutrino oscillations and searches for light long-lived particles, among others. Depending on the project there is a mix of analytical and numerical calculations. Please contact me to discuss possible projects.

Quantum simulation using donor-based quantum dots

Phosphorus-doped silicon quantum dots fabricated with scanning tunnelling microscopy lithography show promise for analogue quantum simulation. We will be performing research on potential applications of these devices for analogue quantum simulation of various physical systems.

Fast, high-fidelity spin readout

Electron spin readout requires the application of fast voltages to control the potential of quantum dots. We will be examining the use of machine learning to optimise the accuracy of which we can determine the electron spin state.

Mapping Quantum Algorithms to Spin Qubit Architectures in Silicon

There are a number of small proof-of-principle quantum algorithms which can be considered important for Noisy Intermediate Scale Quantum devices. Many of these are relatively simple to understand, but still need to be implemented on physical devices.  In doing so choices need to be made, such as which qubit in the algorithm matches to which physical qubit in the device, or which how the operations should be performed and optimised in order to achieve the best (lowest error) performance. This project will examine how to map small scale quantum algorithms and protocols to physical devices.

Quantum Algorithms on near-term physical devices

Quantum algorithms have been shown to provide a way of speeding up certain computationally demanding classical algorithms, across an extensive range of problem types, including optimisation, solving linear algebra problems, and factoring large numbers. In these projects we will examine two broad aspects of quantum algorithms: how best can quantum algorithms be formulated to run on near-term physical devices, specifically the silicon hardware being developed at SQC; what other potential real-world applications can quantum algorithms solve. Possible project areas include: the improvement of key quantum algorithm sub-routines, such as the quantum Fourier transform; the optimisation of workhorse quantum algorithms, such as quantum phase estimation; improvements to near-term heuristic quantum algorithms, such as QAOA (quantum approximate optimisation algorithm) and VQE (variational eigensolver); the application of quantum algorithms to industry relevant areas such as finance, transport, and chemistry.

High fidelity 2 qubit gates in atom qubits in silicon (theory/experiment)

Electric-dipole spin resonance is a method to electrically control semiconductor spin qubits. We will be performing combined theoretical and experimental research on the fabrication, control, and measurement of 2 qubits gates using this technique based on phosphorus in silicon quantum dot qubits.

Fast FPGA Simulation of Single Electron Transistor (SET) Model

SQC Hardware and Software Engineering teams develop in-house instrumentation and a software stack to control and readout from phosphorous donor spin qubits. To develop and validate control and measurement algorithms within the software stack, the software team have developed an SET model implemented in python, in collaboration with quantum physicists. Two limitations are the speed of simulation, and lack of test coverage in the hardware stack. This project aims to move the key elements of the SET model into the FPGA. This will allow algorithms to be tested against the full software and instrument stack without requiring an expensive cryogenic fridge as part of the test setup. The model will run in the FPGA in real-time so simulation speed is fast. This project would suit a student who is interested in modelling and FPGA implementation using Mathworks HDL coder.

My research group works in the broad area of theoretical condensed-matter physics with emphasis on nanomagnetism and spintronics. In particular, I focus on topics such as dynamics of skyrmions and other topological spin textures in ferro/antiferromagnets, spintronics with topological insulators, quantum phenomena in low-dimensional spin-orbit systems. The majority of my work either builds on observations made in recent experiments or predicts new phenomena that should be observable in the near future.

Webpage: https://sites.google.com/site/tretiakov/ 

The research in our group is focused on unconventional magnetism. This includes topologically protected spin systems such as skyrmions, or novel multifunctional materials. For example, multiferroics feature a simultaneous electric polarization and magnetic ordering, and both properties can even be switched by each other. I.e., with an applied electric field the magnetic order can be changed and vice versa. This opens new opportunities for technological applications such as new computer hard drives or in spintronics. We are investigating these materials by SQUID magnetometry, optical Laser spectroscopy and neutron scattering, in order to obtain a deeper knowledge about the involved physics.