I am looking for PhD students and postdocs for my new group at the Department of Electrical and Computer Engineering (ECE) and the Centre for Quantum Technologies (CQT) at the National University of Singapore (NUS). My group will be part of the vibrant international research community around CQT. Topics of interest include quantum Shannon theory and statistics, resource theories, quantum cryptography and other technical/mathematical aspects of quantum information. This is an open-ended call and I will consider high-quality applications as they come in.
Please contact me at email@example.com for further information.
- CQT PhD program: I am looking for Physics, Computer Science or Mathematics graduates with strong interest in the mathematical aspects of quantum information, and the skills required to pursue technical questions in quantum Shannon theory and cryptography. The CQT PhD program offers generous funding and great flexibility to its students. More information can be found here: https://www.quantumlah.org/students.
- ECE PhD program: I am looking for Engineering graduates with background in either information theory or cryptography and a keen interest in the intersection between engineering and quantum information. This degree has a significant coursework component. More information can be found here: http://www.eng.nus.edu.sg/graduate/graduate-research-based-programmes/ph-d-master-of-engineering/
- Postdoctoral research fellowships: I am particularly looking for researchers with a strong track-record working on technical aspects of quantum Shannon theory and cryptography, but strong candidates with proven expertise in other aspects of quantum information are also encouraged to apply. Successful applicants will be granted significant independence concerning their research focus and receive generous travel funding. They will be expected to contribute to the group, for example by co-supervising student projects. Positions will initially be offered for two years, with the option to extend.
Our research interests lie in the intersection of information theory, cryptography and quantum mechanics. The main focus is on the mathematical foundations of quantum information theory, for example the study of entropy and other information measures, as well as theoretical questions that arise in quantum communication and cryptography when the available resources are limited.
Inaugural Lecture at CQT
I gave an inaugural lecture as a CQT principal investigator.
Title: Quantifying information - from classical to quantum
: What is information, and what makes it quantum? This almost sounds like a philosophical question, but in this talk I will instead take a mathematical and operational perspective, inspired by the pioneering work of Shannon and many others after him. I will show how our intuitions can be meaningfully formalised for classical information, and that these mathematical formalisations can then take us further and also give us solid footing in the quantum realm where our intuition would otherwise often fail. I will present several recent developments that I contributed to that collectively give us a fruitful new perspective on a fundamental result in quantum information theory, the strong sub-additivity of quantum entropy.
The slides are available here and the talk will be available on youtube soon.
My book collects a lot of the tools we use in our research. It starts by introducing the basic mathematical formalism of quantum theory in finite dimensions and then discusses distance measures and divergences in detail. Particular emphasis is put on Rényi divergences and their related conditional entropies, including smooth entropies. These tools are widely used in quantum information theory and cryptography.
The book has been published by Springer in their series SpringerBriefs in Mathematical Physics. A free electronic version is available at arXiv:1504.00233 and has all the typos and mistakes that have been brought to my attention so far corrected.
Quantum advantage with noisy shallow circuits in 3D
Nature Physics 16, 1007–1008 (2020)
As larger and larger prototypes of quantum computers are being developed, one of the most exciting challenges in the theory of quantum computing is to find computational problems that can be solved by an noisy intermediate-scale noisy quantum devices, but are beyond the capabilities of existing classical computers. In joint work with Robert König, Sergey Bravyi and David Gosset, we show for the first time an unconditional separation between the computational power of noisy quantum circuits of constant depth and classical circuits of depth even growing slowly (but sub-logarithmically) with the problem size. The quantum advantage established in our paper holds for rather general noise models that may include correlated multi-qubit errors with long-range correlations. Our new separation theorem for noisy devices requires various new tools that we believe to be of independent interest in quantum error correction and simplifies the required quantum circuits, making them more amenable for implementation in near-term devices.
Open-access preprint is available here: arXiv:1904.01502
New collaboration with Jacqui Romero at the University of Queensland:
Securing the quantum internet with high-dimensional quantum systems
Our project, funded by the Australian Research Council (DP200102273), aims to develop experimental and theoretical tools for increasing security in the future quantum networks. This project expects to generate new knowledge in the area of quantum communication by leveraging on the properties of high-dimensional quantum systems. Expected outcomes of this project include novel protocols for quantum secret sharing that are resistant to experimental noise and an experimental implementation of such protocols.