Computation with Coherent States via Teleportations to and from a Quantum Bus

TL;DR

This paper demonstrates the use of one-bit teleportations in quantum bus computation to perform universal gates, encode qubits, and generate entangled states efficiently, with resource advantages over previous methods.

Contribution

It introduces a resource-efficient scheme for universal gates on a quantum bus and novel methods for encoding qubits and creating large entangled states via teleportation.

Findings

Lower resource usage than previous schemes

Efficient encoding of qubits into a quantum repetition code

Ability to produce high-fidelity outputs through post-selection

Abstract

In this paper we present results illustrating the power and flexibility of one-bit teleportations in quantum bus computation. We first show a scheme to perform a universal set of gates on continuous variable modes, which we call a quantum bus or qubus, using controlled phase-space rotations, homodyne detection, ancilla qubits and single qubit measurement. The resource usage for this scheme is lower than any previous scheme to date. We then illustrate how one-bit teleportations into a qubus can be used to encode qubit states into a quantum repetition code, which in turn can be used as an efficient method for producing GHZ states that can be used to create large cluster states. Each of these schemes can be modified so that teleportation measurements are post-selected to yield outputs with higher fidelity, without changing the physical parameters of the system.