Decoherence vs entanglement in coined quantum walks

Abstract

Quantum versions of random walks on the line and cycle show a quadratic improvement in their spreading rate and mixing times respectively. The addition of decoherence to the quantum walk produces a more uniform distribution on the line, and even faster mixing on the cycle by removing the need for time-averaging to obtain a uniform distribution. We calculate numerically the entanglement between the coin and the position of the quantum walker and show that the optimal decoherence rates are such that all the entanglement is just removed by the time the final measurement is made.

11 pages, 6 embedded eps figures; v2 improved layout and discussion

References in corpus (3)

• Quantum walks with infinite hitting times
• Quantum walks on quotient graphs
• Almost uniform sampling via quantum walks

Cited by in corpus (7)

• Decoherence in quantum walks - a review
• Quantum Walks on a Random Environment
• Symmetries and noise in quantum walk
• Mixing Times in Quantum Walks on the Hypercube
• Optimal computation with non-unitary quantum walks
• Quantum Walk-based Generation of Entanglement Between Two Walkers
• Correlation effects in a discrete quantum random walk