These languages allow us to expand the available theoretical tools of quantum computing to match hardware and architectural considerations (including networked and non-unitary protocols), as well as covering the procedures of standard circuit notation, and act as a high-level interface to quantum software. My focus is on using the tools of formal reasoning to advance near-term quantum engineering, and to develop new ways of formulating quantum information processing that match the power and possibilities of the devices now being built.

I also have research interests in the broader theory of physical computation, developing AR theory as a foundational framework for computer science. The ultimate goal is to show how novel physics affects our ability to compute and how, in turn, a computational understanding of fundamental reality impacts back physics.

Since completing my Ph.D at Imperial College, London, I have held positions at Hewlett-Packard, Bristol University, Keio University in Japan, Oxford University, and most recently Durham University.

Research areas

• ZX calculus for the design and verification of quantum algorithms
• Quantum error correction, including lattice surgery and coherent parity check codes
• Quantum architectures and networks

• Abstraction/representation theory
• High-level languages for physics, including quantum causality and thermodynamics

Students:

Current PhD student: Joschka Roffe

Previous PhD students: Shota Nagayama, John-Mark Allen, Miriam Backens

Outreach:

‘The Mysteries of the Universe’, Bright Club February 2016

Publications:

• D. Horsman, V. M. Kendon, S. Stepney, ‘Abstraction/Representation Theory and the Natural Science of Computation’, in M. Cuffaro and S. Fletcher (Eds.), Physical Perspectives on Computation, Computational Perspectives on Physics, Cambridge University Press (in press) (2018).
• N. Chancellor, A. Kissinger, S. Zohren, D. Horsman ‘Coherent parity check construction for quantum error correction’ arXiv:1611.08012 v3 (2018).
• D. Horsman, C. Heunen, M. F. Pusey, J. Barrett, R. Spekkens ‘Can a quantum state over time resemble a quantum state at a single time?’, Proceedings of the Royal Society A 473:20170395 (2017).
• N. de Beaudrap, D. Horsman, ‘The ZX calculus is a language for surface code lattice surgery ’, presented at the 14th International Workshop on Quantum Physics and Logic (QPL), forthcoming in Proceedings. arXiv:1704.08670 (2017).
• J. Roffe, D. Headley, N. Chancellor, D. Horsman, V. Kendon ‘Protecting quantum memories using coherent parity check codes’ arXiv:1709.01866 (2017).
• D. Horsman, V. M. Kendon, S. Stepney, ‘Viewpoint: The Natural Science of Computing’, Communications of the ACM 60(8) 31-34 (2017).
• J-M. Allen, J. Barret, D. Horsman, C. M. Lee, R. Spekkens ‘Quantum common causes and quantum causal models’, Physical Review X 7:031021 (2017).
• D. Horsman, ‘The Representation of Computation in Physical Systems’, in EPSA15 Selected Papers, proceedings of the 5the conference of the European Philosophy of Science Association, Springer (2017).
• D. Horsman, V. M. Kendon, S. Stepney, J. Young, ‘Abstraction and representation in living organisms: when does a biological system compute?’, in G. Dodig-Crnkovic and R. Giovagnoli (Eds), Representation and Reality: Humans, Animals, and Machines, Springer (2017).
• S. Nagayama, A. G. Fowler, D. Horsman, S. Devitt, R. Van Meter, ‘Surface Code Error Correction on a Defective Lattice’, New Journal of Physics 19(2) 023050 (2017).
• S. Abramsky, D. C. Horsman, ‘Demonic programming: a computational language for single-particle equilibrium thermodynamics, and its formal semantics’, in Heunen, Selinger, Vicary (ed.s): Proceedings of the 12th International Workshop on Quantum Physics and Logic, EPTCS 195 116. (2015).
• D. C. Horsman, ‘Abstraction/Representation Theory for heterotic physical computing’, Philosophical Transactions of the Royal Society A 373: 20140224 (2015).
• C. Horsman, S. Stepney, R. Wagner, V. M. Kendon, ‘When does a physical system compute?’, Proceedings of the Royal Society of London A 470:20140182 (2014).
• C. Heunen, C. Horsman, ‘Matrix multiplication is determined by orthogonality and trace’, Linear Algebra and its Applications 439 (12), 4130–4134, (2013)
• R. Van Meter and C. Horsman, ‘A blueprint for building a quantum computer’, Communications of the ACM 56(10), 16-25 (2013).
• T. T. Pham, R. Van Meter and C. Horsman, ‘Optimization of the Solovay-Kitaev algorithm’, Physical Review A 87 (5), 052332, (2013).
• C. Horsman, A. G. Fowler, S. Devitt, and R. Van Meter, ‘Surface code quantum computing by lattice surgery’, New Journal of Physics 14 (12), 123011 (2012).
• K. L. Brown, C. Horsman, V. M. Kendon, and W. J. Munro, ‘Layer by layer generation of cluster states’, Physical Review A 85, 052305 (2012).
• C. Horsman, ‘Quantum picturalism for topological cluster-state computing’, New Journal of Physics 13, 095011 (2011)
• R. Van Meter, J. Touch, and C. Horsman, ‘Recursive quantum repeater networks’, Progress in Informatics 8, 65-79 (2011)
• C. Horsman, K. L. Brown, W. J. Munro, and V. M. Kendon, ‘Reduce, reuse, recycle, for robust cluster state generation ’, Physical Review A 83, 042327 (2011)
• C. Horsman and W. J. Munro, ‘Hybrid hypercomputing: towards a unification of quantum and classical computation’, International Journal of Unconventional Computing 6(5), 417-435 (2010)
• C. Horsman, ‘An introduction to many worlds in quantum computation’, Foundations of Physics 39(8), 869 - 902 (2009)
• C. Horsman and V. Vedral ‘Entanglement without nonlocality’ Physical Review A 76, 062319 (2007)
• C. Horsman and V. Vedral, ‘Developing the Deutsch-Hayden approach to quantum mechanics’ New Journal of Physics 9(5), 12.755 (2007)