Continuous-variable quantum information processing with squeezed states of light

TL;DR

This paper explores continuous-variable quantum information processing using squeezed states of light, demonstrating high-fidelity teleportation, advanced quantum gates, and cluster state entanglement for universal quantum computation.

Contribution

It introduces improved teleportation fidelity, implements a QND interaction gate, and generates cluster state entanglement for continuous-variable quantum computing.

Findings

High-fidelity teleportation of squeezed states

Implementation of a QND interaction gate

Generation of four-mode cluster entanglement

Abstract

We investigate experiments of continuous-variable quantum information processing based on the teleportation scheme. Quantum teleportation, which is realized by a two-mode squeezed vacuum state and measurement-and-feedforward, is considered as an elementary quantum circuit as well as quantum communication. By modifying ancilla states or measurement-and-feedforwards, we can realize various quantum circuits which suffice for universal quantum computation. In order to realize the teleportation-based computation we improve the level of squeezing, and fidelity of teleportation. With a high-fidelity teleporter we demonstrate some advanced teleportation experiments, i.e., teleportation of a squeezed state and sequential teleportation of a coherent state. Moreover, as an example of the teleportation-based computation, we build a QND interaction gate which is a continuous-variable analog of a CNOT gate. A QND interaction gate is constructed only with ancillary squeezed vacuum states and measurement-and-feedforwards. We also create continuous-variable four mode cluster type entanglement for further application, namely, one-way quantum computation.