Entanglement Dynamics in 1D Quantum Cellular Automata

TL;DR

This paper explores entanglement dynamics in 1D quantum cellular automata, proposing minimal physical conditions for their implementation, and demonstrating how non-unitary rules can generate environment-assisted entanglement.

Contribution

It introduces the theory of non-unitary QCA and provides optimal pulse sequences for entanglement distribution in 1D Ising spin chains.

Findings

Minimal physical requirements for unitary QCA in 1D chains

Optimal pulse sequences for information transport

Non-unitary QCA can generate environment-assisted entanglement

Abstract

Several proposed schemes for the physical realization of a quantum computer consist of qubits arranged in a cellular array. In the quantum circuit model of quantum computation, an often complex series of two-qubit gate operations is required between arbitrarily distant pairs of lattice qubits. An alternative model of quantum computation based on quantum cellular automata (QCA) requires only homogeneous local interactions that can be implemented in parallel. This would be a huge simplification in an actual experiment. We find some minimal physical requirements for the construction of unitary QCA in a 1 dimensional Ising spin chain and demonstrate optimal pulse sequences for information transport and entanglement distribution. We also introduce the theory of non-unitary QCA and show by example that non-unitary rules can generate environment assisted entanglement.