Moments of Coinless Quantum Walks on Lattices

Abstract

The properties of the coinless quantum walk model have not been as thoroughly analyzed as those of the coined model. Both evolve in discrete time steps but the former uses a smaller Hilbert space, which is spanned merely by the site basis. Besides, the evolution operator can be obtained using a process of lattice tessellation, which is very appealing. The moments of the probability distribution play an important role in the context of quantum walks. The ballistic behavior of the mean square displacement indicates that quantum-walk-based algorithms are faster than random-walk-based ones. In this paper, we obtain analytical expressions for the moments of the coinless model on $d$-dimensional lattices. The mean square displacement for large times is explicitly calculated for the one- and two-dimensional lattices and, using optimization methods, the parameter values that give the largest spread are calculated and compared with the equivalent ones of the coined model. Although we have employed asymptotic methods, our approximations are accurate even for small numbers of time steps.

13 pages, 1 figure

References in corpus (6)

• Limit distributions of two-dimensional quantum walks
• Weak Limit of the 3-State Quantum Walk on the Line
• Limit distributions of three-state quantum walks: the role of coin eigenstates
• One-Dimensional Coinless Quantum Walks
• Search on a Hypercubic Lattice through a Quantum Random Walk: II. d=2
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• Chirality from quantum walks without quantum coin
• Multiparticle quantum walk with a gas-like interaction
• Second-order topological insulator in a coinless discrete-time quantum walk
• Discrete-Time Quantum Walks on Oriented Graphs
• Path-sum solution of the Weyl Quantum Walk in 3+1 dimensions