Coherent modification of entanglement: benefits due to extended Hilbert space

TL;DR

This paper demonstrates that leveraging extended Hilbert spaces and continuous time quantum random walks can significantly enhance the efficiency of multiqubit entanglement operations in quantum computing systems.

Contribution

It introduces a method to utilize non-local states in extended Hilbert spaces for faster entanglement manipulation, exemplified by a three-qubit Toffoli gate and superconducting qubits.

Findings

Speed-up in multiqubit entanglement operations

Effective use of non-local states via quantum random walks

Application to superconducting qubit systems

Abstract

A quantum computing system is typically represented by a set of non-interacting (local) two-state systems - qubits. Many physical systems can naturally have more accessible states, both local and non-local. We show that the resulting non-local network of states connecting qubits can be efficiently addressed via continuous time quantum random walks, leading to substantial speed-up of multiqubit entanglement manipulations. We discuss a three-qubit Toffoli gate and a system of superconducting qubits as an illustration.