10/09/2004, 15:00 — 16:00 — Sala P4.35, Pavilhão de Matemática
Pedro Ribeiro, École Polytechnique
Quantum walks with two quantum coins
This work presents quantum walks which are the quantum counterparts
of classical random walks. Quantum walks are first defined on
general graphs and the possibility of very different behavior
between a classical random walk and its quantum analogue is
illustrated with a simple graph. A generalization of the quantum
walk protocol for a particle in a one-dimensional chain, by using
several types of biased quantum coins, is presented. We study the
evolution of the system when different types of sequences are
applied. Quasiperiodic sequences, following the Fibonacci
prescription, are of particular interest, leading to a
sub-ballistic wave function spreading. In contrast, random
sequences leads to diffusive spreading, similar to the classical
random walk behavior. We describe qualitatively how to
experimentally implement these processes.
Apoiado por: Phys-Info (IT), SQIG (IT), CeFEMA e CAMGSD, com financiamento de FCT, FEDER and EU FP7, especificamente via o Doctoral Programme in the Physics and Mathematics of Information (DP-PMI), os projectos estratégicos FCT PEst-OE/EEI/LA0008/2013 e UID/EEA/50008/2013, o projecto IT QuSim, o projecto CRUP-CPU CQVibes, a Acção de Coordenação FP7 QUTE-EUROPE (600788) e os projectos FP7 Landauer (GA 318287) e PAPETS (323901).