I am a joint postdoctoral research fellow in quantum foundations and quantum information at the Perimeter Institute and the Institute for Quantum Computing. I grew up in Akureyri, Iceland, and later in Cambridge, UK. I completed my undergraduate and masters' degree in Physics at Imperial College London, UK, in 2018 and did my masters' thesis at the University of Freiburg, Germany, on a one-year Erasmus exchange program, in the group of Prof Dr Andreas Buchleitner. I completed my PhD in Computer Science at the University of Oxford in 2022, under the supervision of Prof Giulio Chiribella and Prof Jonathan Barrett, with a few months as a visiting PhD student at the University of Hong Kong. In 2021, alongside my PhD, I worked as an independent research consultant in quantum communications for Ofcom, the UK Office for Communications. From 2022-23, I was a postdoctoral researcher at the University of Tokyo, in the group of Prof Mio Murao. In addition to physics, I have also studied non-degree courses in violin performance as an Ash Music Scholar at the Royal College of Music, London, UK, in German language at the University of Freiburg, Germany, and in Chinese language as a Huayu Scholar at the National Kaohsiung Normal University, Taiwan. As a musician, I have co-composed and released an original album, and performed as a violinist at various venues. In my spare time, I like learning languages and cooking elaborate meals, as well as doing exercise and mindfulness meditation.
***If you are an undergraduate or masters' student interested in working with me on a summer internship/masters' project please feel free to contact me via email!*** Student supervision: 4. Tatsuki Odake, Higher-order quantum transformations of Hamiltonian dynamics, MSc Thesis in Physics, University of Tokyo, 2022–24. Co-supervisor with Prof Mio Murao. 3. Yan Zhong, Undergraduate Summer Research Project, Department of Computer Science, The University of Hong Kong, 2020. Co-supervisor with Prof Giulio Chiribella. 2. Anthony Munson, Communication advantages for the superposition of asymptotically long sequences of quantum channels, MSc Thesis in Computer Science, University of Oxford, 2020. Co-supervisor with Prof Giulio Chiribella. 1. Wenxu (Mike) Mao, Quantum superposition of communication lines, BSc Thesis in Computer Science, The University of Hong Kong, 2019. Co-supervisor with Prof Giulio Chiribella. Tutorials: 2. Class Tutor for the Quantum Computer Science MSc Course, University of Oxford Oct. 2019 – Dec. 2019. 1. Class Tutor for the Quantum Information BSc Course, University of Oxford Jan. 2019 – Mar. 2019.
I am interested in the foundational structures of quantum theory and how they can be used in novel ways for advantages in quantum computation and communication. Specifically, my research interests are currently in higher-order quantum computation (the quantum analogue of functional programming) and quantum causality. In the past few years, I have worked on the following topics: causality in quantum theory - indefinite causal order - higher-order quantum algorithms - quantum communication with coherent control of transmission lines - quantum resource theories - quantum diagrammatic languages - quantum machine learning and quantum neural networks.
- Odake, T., Kristjánsson, H., Soeda, A., & Murao, M. (2023). Higher-order quantum transformations of Hamiltonian dynamics. arxiv:2303.09788v5
- Kristjánsson, H., Zhong, Y., Munson, A., & Chiribella, G. (2022). Quantum networks with coherent routing of information through multiple nodes. arxiv:2208.00480v2
- Vanrietvelde, A., Ormrod, N., Kristjánsson, H., & Barrett, J. (2022). Consistent circuits for indefinite causal order. arxiv:2206.10042v2
- Howl, R., Akil, A., Kristjánsson, H., Zhao, X., & Chiribella, G. (2022). Quantum gravity as a communication resource. arxiv:2203.05861v1
- Kristjánsson, H., Mao, W., & Chiribella, G. (n.d.). Witnessing latent time correlations with a single quantum particle. Physical Review Research, 3(4). doi:10.1103/physrevresearch.3.043147
- Vanrietvelde, A., Kristjánsson, H., & Barrett, J. (n.d.). Routed quantum circuits. Quantum, 5, 503. doi:10.22331/q-2021-07-13-503
- Rubino, G., Rozema, L. A., Ebler, D., Kristjánsson, H., Salek, S., Allard Guérin, P., . . . Walther, P. (n.d.). Experimental quantum communication enhancement by superposing trajectories. Physical Review Research, 3(1). doi:10.1103/physrevresearch.3.013093
- Kristjánsson, H., Chiribella, G., Salek, S., Ebler, D., & Wilson, M. (2020). Resource theories of communication. New Journal of Physics, 22(7), 073014. doi:10.1088/1367-2630/ab8ef7
- Higher-order transformations and the causal structure of quantum processes, Quantum Foundations, 2023/10/06, PIRSA:23100106
- Quantum gravity as a communication resource, QPL 2023, Henri Poincaré Institute, Paris, France, 2023/07/17
- Higher-order quantum transformations of Hamiltonian dynamics, Inria Saclay - Île-de-France Research Centre, Paris, France, 2023/07/13
- Introduction to Indefinite Causal Order, Benasque Quantum Information 2023, Centro Ciencias de Benasque Pedro Pascual, Benasque, Spain, 2023/06/29
- Witnessing latent time correlations with a single quantum particle, University of Geneva, Geneva, Switzerland, 2023/04/24
- Quantum gravity as a communication resource, QISS Spring School 2023, Château de Goutelas, France, 2023/04/18