Professor Doherty is recognised internationally for his innovative contributions to theoretical physics. He is one of the pioneers of the field of quantum control and has made seminal contributions to quantum information theory. In quantum control he was the first to apply ideas from classical control which is ubiquitous from aircraft to precision measurement to the science of quantum systems. This work was a very early forerunner of the current experimental and theoretical programs in the control of quantum systems. Professor Doherty's work emphasised that adaptability and feedback would be essential to any quantum technology and was ahead of its time in emphasising the need to begin engineering quantum systems. Professor Doherty is well known for his extensive collaborations with experimentalists in wide range of systems from quantum optics, including cavity QED and optomechanical systems, to condensed matter, including circuit QED and semiconductor quantum dots.

Major funding support

Professor Doherty has held a career total of 5 ARC Discovery Project grants and a Future Fellowship. He is an investigator in the U. S. government IARPA-funded program on Multi-Qubit Coherent Operations using electron spins, funded at $27.5M over 4 years (2010-2014) with $1M/yr to Sydney. This is the most significant international research effort in this area, originally headquartered at Harvard, now at the Niels Bohr Institute and involving Chief Investigators from Harvard, Maryland, UCSB, Delft, Tokyo, Basel, Purdue, and 3 CIs at the University of Sydney.

Overall, Professor Doherty’s career total of competitive research funding is $55.3M (grants on which he is a Chief Investigator), for which the Sydney budget component exceeds $11M.

Mentoring and research training

Along with Professor Stephen Bartlett and Associate Professor Steven Flammia, Professor Doherty leads the theoretical quantum physics group at the University of Sydney. The group is 26 strong, with 5 postgraduate Honours students this year, 11 PhD students and 7 postdoctoral researchers, including two that have been awarded ARC Discovery Early Career Researcher Awards and one University of Sydney Postdoctoral Fellowship. Currently he supervises 11 PhD students (4 for whom as principal supervisor). He has graduated 10 PhD students over his career, four as principal advisor, and one research Masters Student.

Professor Doherty has a very strong record of mentoring younger researchers to the group.  He was the mentor and internal advocate for two successful University of Sydney Postdoctoral Fellowships in 2013. If you are interested in working or studying with Professor Doherty, please contact him.

Qualifications: 
PhD, University of Auckland, New Zealand (2000)
BSc ( Hons), University of Canterbury, New Zealand (1996)
Theory of quantum measurement and control in semiconductor qubits 

Grand challenge: Develop design principles for robust control of hybrid quantum systems and demonstrate their utility in experimental applications. 

Together with the team of Amir Yacoby at Harvard, we are investigating how electrons in a semiconductor chip can be used to store and process quantum information. These spins have the potential for very long coherence times relative to gate operation times, but experience a noisy environment from the atomic nuclei of all the surrounding semiconductor atoms. Left on their own, these nuclei will destroy the quantum nature of the electron very quickly, in a few billionths of a second. We have invented a new technique where we use the electron to monitor its environment, very quickly learn the effect of all of these nuclei, and then use this information to compensate for its effect. This research was published in 2014 in Nature Communications. 

Controlling electron spin in semiconductor quantum devices 

Grand challenge: Realise new and otherwise inaccessible regimes of physics through the construction of hybrid quantum systems. 

Single electrons individually trapped and manipulated in semiconductors are one of the most promising avenues for engineered quantum systems. This project investigates the ways in which the magnetic moment, or spin, of these electrons can be controlled, either electrically or through applying microwaves, and how acoustic vibrations, or phonons, affect this control. These results highlight the role of the phononic environment in understanding the driven dynamics of coherent quantum systems and provide a path for transducing quantum information between photons, phonons, spins and charge. The work is a strong collaboration between theorists CI Tom Stace (UQ) and CI Andrew Doherty (Sydney) and the experimental team of CI Reilly’s laboratory (Sydney). This work has been published in Nature Communications.

Quantum matter 

Grand challenge: Address key fundamental theoretical questions.

Grand challenge: Preserving quantum states against decoherence indefinitely.

The Synthetic Quantum Systems program aims to address the key fundamental theoretical questions: how can we create and harness quantum matter to process information in new ways, and what new principles can we learn from a classification of this matter? We theoretically construct and explore new phases of strongly-coupled quantum many-body systems that exhibit powerful exotic properties such as topological order, and direct these properties towards applications such as quantum memories and processors.

Quantum chemistry with quantum simulators 

Grand challenge: Produce programmable quantum simulators capable of outperforming the best classical technology. 

One of the most anticipated applications of quantum simulations is to increase the accuracy of calculations in quantum chemistry. For example, the energy of metastable transition states of even rather small molecules can be critical to understanding industrially significant chemical reactions that involve catalysts. The highest accuracy simulations performed currently to estimate such energies are termed full configuration interaction simulations, and if they could be performed on systems involving as few as one hundred orbitals, this would already be an enormous advance. This work, in collaboration with researchers at the University of Sherbrooke and Microsoft Research, aims to investigate the usefulness of digital quantum simulators for performing full configuration interaction simulations, as compared to classical devices. 

Current Supervision


Doctor Philosophy - Principal Advisor


Doctor Philosophy - Principal Advisor

Completed Supervision

(2015)
Honours project - Principal Advisor

Australia-China Group Mission in the Control of Quantum Systems

Department of Industry, Innovation, Climate Change, Science, Research and Tertiary Education (Fed)/Australia China Science and Research Fund - Group Missions (2012)

Australian Research Council Future Fellowship

(2010 to 2013)

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