Come and join us!
At QSCITECH we have a vibrant environment for scientific training – with many opportunities and activities to train to excel at the highest international levels. Students have available to them potential MRes, PhD scholarships, their own travel/research budget (PhD), weekly seminars and regular journal clubs. Below we list possible PhD projects and interested MRes, PhD students/postdoctoral researchers should contact the relevant listed academic for opportunities surrounding a particular PhD project.
MRes Opportunities: Macquarie University provides a unique Master of Research with one year coursework and one year research. Funding is available to support students during their MRes studies and entry into Year 2 of the MRes to focus on research alone is encouraged – particularly for international students wishing to progress to a PhD. Applications are primarily due Oct & March each year. Current MRes research projects can be viewed here.
PhD Opportunities: Macquarie University provides a very generous PhD scholarship for 3 year PhD studies. These are quite competitive and applications must be made each year before Aug 31.
To apply for MRes/PhD studies in quantum science and technology first choose a suitable PhD project below and send your CV/Resume/undergraduate/postgraduate transcript to the associated academic supervisor – Subject: MRes/PhD Studies Application.
We are currently offering the following PhD projects:
Quantum Simulation of Quantum Chemistry
Dr. Dominic W Berry: Macquarie University
Prof. Alán Aspuru-Guzik: Harvard University
There are an enormous variety of technological challenges, such as renewable energy and pharmaceutical design, that could be solved if one could rapidly simulate molecules. The problem is that quantum systems are fundamentally difficult to simulate on normal “classical” computers. This led Feynman to propose the idea of quantum computers . Later Lloyd gave a general quantum simulation algorithm , but it was Aspuru-Guzik and co-workers who showed how to simulate quantum chemistry on a quantum computer . Unfortunately, this algorithm was relatively slow .
The goal of this PhD project is to develop techniques for quantum computers to simulate quantum chemistry that are much faster, and could enable quantum computers to simulate much larger molecules. The basic techniques to achieve this have been presented in a pair of papers by Berry and Aspuru-Guzik , and are based upon the ability to exponentially accelerate a numerical integral. This project will fully develop these techniques and devise ways to further improve the complexity, for example by showing how to better choose integration grids, and tailoring the algorithms for real molecules.
 R. Feynman, International Journal of Theoretical Physics 21, 467 (1982).
 S. Lloyd, Science 273, 1073 (1996).
 A. Aspuru-Guzik, A. D. Dutoi, P. J. Love, and M. Head-Gordon, Science 309, 1704 (2005).
 D. Wecker, B. Bauer, B. K. Clark, M. B. Hastings, and M. Troyer, Phys. Rev. A 90, 022305 (2014).
 R. Babbush, D. W. Berry, I. D. Kivlichan, A. Y. Wei, P. J. Love, and A. Aspuru-Guzik, arXiv:1506.01020; arXiv:1506.01029 (2015).
Optical trapping and Levitation of nanoparticles
A/Prof Gabriel Molina-Terriza *: Macquarie University
A/Prof Thomas Volz: Macquarie University
Prof. Jason Twamley: Macquarie University
Prof. Oriol Romero-Isart: Univ. Innsbruck
In the Quantum Nanophotonics laboratories of Macquarie University, we have started a series of experiments showing that the the Physics of the Star Wars’ “tractor beam” was possible. Using electromagnetic radiation (an optical beam) we have managed to capture a small particle and move it around without physically touching the particle. This technique, which has led to a Nobel prize in physics and a whole new industry in biotechnology, could allow us to explore new physical regimes when we combine it with cooling the particle to the its quantum ground state. Nevertheless, the possibility of trapping small particles in vacuum (optical levitation) is still a battleground for physicists.
In this project we will set-up an experiment to trap and manipulate small particles in water, air and vacuum. We will use a continuous wave laser and a nanopositioner in order to beat the gravitation and van der Waal’s forces locking the particles to the substrates. We will explore different experimental techniques to increase the optical forces to levitate smaller and smaller dielectric particles.
This project is part of an ambitious project to observe quantum effects in dielectric particles, by isolating them from any decoherence due to the environment. Over a 3 year PhD program, the candidate will have the opportunity to use these techniques to cool the dielectric particle to ultralow temperatures and observe the quantum properties of a macroscopic object.
 Near-field Levitated Quantum Optomechanics with Nanodiamonds: Strong Single-Photon Coupling at Room Temperature arXiv:1505.03363
Quantum control of plasmonic structures with entangled photon states
A/Prof Gabriel Molina-Terriza*: Macquarie University
Prof. Javier Aizpurua: EHU
Prof. Anton Zeilinger: Univ. of Vienna
The group of Prof. Gabriel Molina-Terriza (Macquarie University, Australia) offer a Ph.D. position to work in the field of quantum nanophotonics. The successful candidate will study both experimentally and theoretically the interaction of quantum states of light with nanoplasmonic structures. This is an exciting new field of research where several groups in the world are working to control the quantum properties of small metallic nanostructures. The extreme sensitivity of these quantum devices make them suitable to become the next generation of biosensors or to perform very precise measurements of electric and magnetic fields.
There are several PhD positions available in this research line, some of them could be carried out as a co-tutelle with other Universities, including the University of the Vasque Country (EHU) and the University of Vienna. The experimental research activity will be mainly developed in Macquarie University, where the candidate will benefit from the facilities in the group of Molina-Terriza, including a fully equipped quantum optics laboratory and nanofabrications and characterization facilities.
 Measurement and shaping of biphoton spectral wavefunctions, arXiv:1503.08629
 Angular momentum-induced circular dichroism in non-chiral nanostructures Nature Communications
 Twisted Photons Nature Physics
Exploring Phase Diagrams of Anyonic Systems
When you exchange a pair of identical bosons, you can’t tell the difference. When you exchange a pair of fermions once you can tell, but exchange them twice, and you’re back to where you started. Exchange a pair of anyons, and almost anything could happen. Anyons are a kind of exotic particle (or excitation) found in two-dimensional systems, and are defined as any particle showing non-bosonic, non-fermionic exchange behaviours . For some of the simplest, you might need to swap a pair three, four, or more times to get back to your original state.
Very little is known about the behaviours of large numbers of anyons, but recent developments in the simulation techniques known as tensor network algorithms are finally permitting us to start to explore their properties. In this project you will further develop and apply these techniques [2,3] to study unexplored anyonic systems on a variety of manifold topologies and characterise their behaviours .
 A. Kitaev, Ann. Phys. 321, 2 (2006).
 R. N. C. Pfeifer and S. Singh, arXiv:1505.00100 [cond-mat.str-el] (2015).
 R. N. C. Pfeifer, arXiv:1505.06266 [cond-mat.str-el] (2015).
 R. N. C. Pfeifer, arXiv:1505.06928 [cond-mat.str-el] (2015).
Self-Modifying Tensor Network Algorithms
Tensor network algorithms are one of the most powerful techniques for the study of low-dimensional quantum systems. Indeed, one of the most successful numerical methods of all time, the Density Matrix Renormalisation Group algorithm , is a tensor network algorithm. However, the effectiveness of the algorithm depends very strongly on the extent to which its structure reflects the underlying (and possibly unknown) physics as well as the spatial structure of the system under study. The design of successful tensor network algorithms is very much a skilled art.
Using some of the latest developments in tensor network design [2,3], this project will investigate whether it is possible to make the networks design themselves, detecting both the spatial and entanglement structure of a physical system and organizing themselves appropriately.
 U. Schöllwock, Ann. Phys. 326, 96–192 (2011).
 G. Evenbly and R. N. C. Pfeifer, Phys. Rev. B 89, 245118 (2014).
 R. N. C. Pfeifer, J. Haegeman, and F. Verstraete, Phys. Rev. E 90, 033315 (2014).
A/Prof. Michael Steel: Macquarie University
Dr Luke Helt: Macquarie University
In quantum mechanics, interference occurs whenever a given experimental outcome can come about in two or more ways. This means for instance that two photons incident from opposite sides of an oblique two-way mirror always leave as a pair. Weirdly, the two photons need not even reach the mirror at the same time: the interference occurs as long as we can’t tell which one arrived first. This surprising phenomenon is at the heart of photonic approaches to quantum information processing, including including quantum metrology, boson sampling, and optical quantum computing. These operations have been thoroughly investigated in real space, but there are even stranger analogs which are much less studied: it should be possible to see interference of two photons of completely different colour.
In this project we will explore the description and design of quantum logic gates and processes in the frequency and time domains. We will design nonlinear optical devices that enable the quantum interference of photons of different frequencies, including the optimisation and suppression of competing
frequency conversion processes. Connections to classical optics will be pursued to facilitate ease of laboratory characterisation and implementation. There will be close interaction with experimental teams working on these and similar ideas.
Z. Chaboyer, T. Meany, L. G. Helt, M. J. Withford, and M. J. Steel, Tunable quantum interference in a 3D integrated circuit Scientific Reports 5, 9601:1–5 (2015)
L. G. Helt, J. E. Sipe, and M. J. Steel, Spontaneous parametric downconversion in waveguides: What’s loss got to do with it? New Journal of Physics 17, 013055:1–17 (2015)
M. J. Collins, C. Xiong, I. H. Rey, T. D. Vo, J. He, S. Shahnia, C. Reardon, T. F. Krauss, M. J. Steel, A. S. Clark, and B. J. Eggleton, Integrated spatial multiplexing of heralded single photon sources Nature Communications 4, 2582:1–7 (2013)
M. K. Dezfouli, M. J. Steel, J. E. Sipe and M. M. Dignam, Heisenberg treatment of pair-generation in lossy coupled-cavity systems Physical Review A 90, 043832:1–12 (2014)
Simulation of highly interacting realistic quantum spin systems in solid-state quantum technology devices
Prof. Jason Twamley*: Macquarie University
Dr Robert Pfeifer: Macquarie University
Spins in solid state are a beautiful example of an interacting quantum many-body system. Many of our technologies today are crucially dependent on the properties of such systems, and developing novel engineered states of quantum spin systems is a fast moving research field in the development of tomorrow’s quantum technologies e.g. quantum computing, sensing and communication. With the advent of diamond based spin systems (e.g. Nitrogen Vacancy defects), accessing and controlling solid-state spin systems has greatly improved as one is able to polarize, manipulate and read out spin systems near to an NV defect using a combination of microwave, laser and radio frequency pulses. However, simulating realistic interacting many body spin systems on a classical computer is extremely challenging and brute force simulations can only model up to 15-20 spins.
In this PhD project we will develop numerical methods to efficiently simulate thousands of such spins using numerical methods such as Density Matrix Renormalization Group. We will work closely with experiments to simulate the dynamics of the large complex interacting spin systems which arise in quantum computing, quantum sensing and quantum communication, for example in diamond quantum devices.
 D. Stanek, C. Raas, and G.S. Uhrig, Dynamics and decoherence in the central spin model in the low-field limit, Phys. Rev. B 88, 155305 (2013);ibid 90, 064301 (2014).
 R. S. Said, D. W. Berry, and J. Twamley, Nanoscale magnetometry using a single-spin system in diamond, Phys. Rev. B 83, 125401 (2011); G. Waldherr, J. Beck, P. Neumann, R. S. Said, M. Nitsche, M. L. Markham, D. J. Twitchen, J. Twamley, F. Jelezko & J. Wrachtrup, High-dynamic-range magnetometry with a single nuclear spin in diamond , Nature Nanotechnology 7, 105 (2012).
 R.N.C. Pfeifer, P Corboz, O Buerschaper, M Aguado, M Troyer, G Vidal, Simulation of anyons with tensor network algorithms, Phys. Rev. B 82, 161107 (2010).
Single Spin Sensing with Nano Diamonds
Dr Thomas Volz*: Macquarie University
Dr Carlo Bradac: Macquarie University
The Quantum Materials and Applications group at Macquarie University Sydney is looking for an interested and highly motivated individual to work on a PhD project on nanoscale single-spin sensing with defect centres in (nano-)diamonds. The technique of using single NV centres for magnetic field sensing down to the nT/sqrt(Hz) level in different contexts is well established in the field and has been applied to different scenarios including magnetic-field sensing in biological contexts . This project aims at implementing a low-temperature single-spin sensing platform based on a closed-cycle cryostat and a commercially available AFM platform. The platform will be used for studying novel and exotic solid-state materials and for exploring their potential for real-world applications. The student should bring a strong interest in technology and a good understanding and working knowledge of quantum mechanics. Previous experience in the field is a plus but not absolutely necessary.
If you are interested in the project please contact Dr Thomas Volz (firstname.lastname@example.org) and/or Dr Carlo Bradac (email@example.com).
 L. Rondin, J.-P. Tetienne, T. Hingant, J.-F. Roch, P. Maletinsky, and V. Jacques Magnetometry with nitrogen-vacancy defects in diamond Rep. Prog. Phys. 77, 056503 (2014)
Numerical Techniques for Long-Range Hamiltonians
Tensor network algorithms are some of the most powerful general techniques ever developed for the study of low-dimensional quantum systems. However, the study of systems with long-range (polynomial) interactions remains challenging, and existing algorithms either specialise to short-range interactions (e.g. MERA ) or introduce an effective cut-off (e.g. DMRG with MPO ). Almost all physical systems exhibit polynomial interactions and to explore novel quantum correlations mediated by such long range interactions has so far proved feasible only in relatively small systems. In quantum computers, many types of quantum error correction typically do not correct errors due to long range interactions and so its important to be able to gauge how such interactions can build up large correlations in the various quantum systems upon which quantum computers are based.
In this project, you will work to develop a real-space tensor network algorithm for large spin systems with polynomial interactions. You will acquire skills and experience in the design and implementation of tensor network algorithms, and in the application of ideas in real-space renormalisation group theory to lattice systems . You will then take these powerful methods and apply them to various detailed physical systems relevant to quantum information processing [4,5]. There is also the potential to collaborate with experimental groups to probe the accuracy of the simulations from an experimental point of view. Subject to interest, there may also be opportunities to work with anyonic systems, and to investigate the role of self-organisation in the design of tensor network algorithms.
Parity-Time symmetry phase transitions in quantum opto-acoustic systems
Conventional quantum mechanics of isolated systems is built upon the assumption of a Hermitian Hamiltonian to ensure physical real-valued energy levels. Parity-Time symmetric (PT) quantum systems are attracting enormous interest in the community. PT systems, while not Hermitian, still exhibit real eigenenergies and display complex and interesting behaviors. In particular such systems support a discontinuous phase transition when a control parameter is varied and PT symmetry is broken. Surprisingly, PT-symmetry breaking enables potentially very useful properties for technologies eg. non-reciprocal optical devices , enhancement of optomechanical coupling , and phonon/photon enhanced couplings.
In this project, we will explore the novel phase transitions that appear in PT related materials and in particular in systems that couple light to elastic vibrations (phononics) [4,5], and also to spin (spintronics). Such systems will have many potential applications ranging from novel types of sensors through to the quenching of quantum phase transitions. During the project you will learn techniques (analytic and numeric), in advanced photonics and acoustics, techniques related to quantum spin physics and the design and simulation of ultra-precise sensors .