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My research interest is in quantum computation, in particular computational models. One object of study in this field is the oneway quantum computer, a scheme of quantum computation consisting of local measurements on an entangled universal resource state. The questions I ask are ``What are the elementary building blocks of the oneway quantum computer? What is their composition principle?'' I hope that the answer to these questions will give clues for how to construct novel quantum algorithms. Another model of quantum computation that I study are quantum cellular automata (QCA). I am, for example, interested in the question of whether and what type of quantum algorithms can be encoded the shape of the boundary of a finitely extended quantum cellular automaton.
I have invented the oneway quantum computer (QCc) together with Hans Briegel (UK patent GB 2382892, US patent 7,277,872). The QCc is a scheme of universal quantum computation by local measurements on a multiparticle entangled quantum state, the socalled cluster state. Quantum information is written into the cluster state, processed and read out by onequbit measurements only. As the computation proceeds, the entanglement in the resource cluster state is progressively destroyed. Measurements replace unitary evolution as the elementary process driving a quantum computation.
I also work in the field of faulttolerant quantum computation. Errorcorrection is what a largescale quantum computer spends most of its computation time with, and it is important to devise errorcorrection methods which allow for a high error threshold at a moderate operational overhead. My research interest is in faulttolerance for quantum systems with a geometrical constraint, e.g. lowdimensional lattice systems, and in topological methods.
R. Raussendorf and J. Harrington, Faulttolerant quantum computation with high threshold in two dimensions, arXiv:quantph/0610082, Phys. Rev. Lett. 98, 150504 (2007).
R. Raussendorf, J. Harrington, K. Goyal A faulttolerant oneway quantum computer, arXiv:quantph/0510135, Ann. Phys. (N.Y.) 321, 2242 (2006).
R. Raussendorf, S. Bravyi, J. Harrington, Longrange quantum entanglement in noisy cluster states, arXiv:quantph/0407255 , Phys. Rev. A 71, 062313 (2005).
R. Raussendorf and H.J. Briegel, Computational model underlying the oneway quantum computer, arXiv:quantph/0108067, Quant. Inf. Comp. 6, 443 (2002).
R. Raussendorf and H.J. Briegel, A oneway quantum computer, (preprint version is entitled ``Quantum computing via measurements only'', arXiv:quantph/0010033), Phys. Rev. Lett. 86, 5188 (2001).
H.J. Briegel and R. Raussendorf, Persistent Entanglement in Arrays of Interacting Particles , arXiv:quantph/0004051, Phys. Rev. Lett. 86, 910 (2001).
A complete list of my publications can be found here.
I received my Diploma/Master degree in Physics from the Ruprecht Karls University in Heidelberg, Germany in 1997. My thesis Diploma thesis is on ``A Linear SigmaModel for Vector and Axial Vector Mesons'' (lowenergy quantum chromodynamics). In 1998/99 I did community service at the German Cancer Research Center Heidelberg. In 2003 I obtained my PhD from the Ludwig Maximilians University in Munich, Germany (summa cum laude). My PhD thesis is on measurementbased quantum computation. From 2003 to 2006 I was postdoc at Caltech and I am presently postdoc at the Perimeter Institute for Theoretical Physics in Waterloo, Canada. I will join the Physics and Astronomy department at the University of British Columbia as Assistant Professor in January 2008.