An Isaac Newton Institute Workshop

Quantum Information Theory: Present Status and Future Directions

Entanglement and decoherence in coined quantum walks

25th August 2004

Authors: Peter Knight (Imperial College London), Ivens Carneiro (Imperial College), Mathieu Girerd (Imperial College), Meng Loo (Imperial College), Xibai Xu (Imperial College), Viv Kendon (Imperial College), Eugenio Roldan (University of Valencia), John Sipe (University of Toronto)


Quantum walks, both discrete (coined) and continuous time, form the basis of several recent quantum algorithms. We review the specific quantum properties of quantum walks and their sensitivity to decoherence. We then examine the entanglement properties of quantum walks in various dimensions (lines, 2D lattices and trees) using entropic characterizations generated from the subsystem density matrices of the walker position-coin state correlations.