Research press release


Nature Photonics

Step towards city-wide quantum teleportation



2つの研究グループが、この点を克服するために、独立してフィードバック機構と同期機構を開発し、テレポーテーション実験を可能にした。Qiang ZhangとJian-Wei Panたちは、合肥(中国)で現地試験を実施し、ファイバー内の信号光の減衰速度を最小限にするため現行の通信ネットワークに用いられている通信波長の光を用いた。Wolfgang Tittelたちはカルガリー(カナダ)で試験を行い、通信波長の光子と波長795 nmの光子を用いた。このため、Tittelたちの量子テレポーテーション実験の方が、ZhangとPanたちの実験よりも転送速度が速かった。しかし、忠実度はTittelたちの方が低かった。

同時掲載のNews & Views記事で、Frederic Grosshansは次のように述べている。「今回の2つの実験は、都市レベルの距離のテレポーテーションが技術的に実現可能であることを明確に示している。今回の研究をもとに、間違いなく多くの興味深い量子情報実験が構築されるであろう」。

Quantum teleportation - the remote transfer from one location to another of quantum information encoded into particles of light - over several kilometres of optical fibre networks in the cities of Hefei, China and Calgary, Canada is reported in two papers published online in Nature Photonics this week. The two independent studies show that quantum teleportation across metropolitan networks is technologically feasible, and pave the way towards future city-scale quantum technologies and communications networks, such as a quantum internet.

Quantum teleportation over fibre optic networks has the potential to greatly improve the security and strength of internet connections. However, long-distance quantum teleportation using a fibre network requires independent light sources, and this presents a technological challenge: the light beam from one source needs to remain indistinguishable to the light beam from the other source after travelling through several kilometres of fibre that is laid through a changing environment.

To overcome this, the research groups independently developed several feedback and synchronization mechanisms to enable their teleportation experiments. Qiang Zhang, Jian-Wei Pan and colleagues implemented their field test in Hefei, China and used light at a telecommunication wavelength (as used in current telecommunications networks) to minimize the rate at which the signal light loses intensity in the fibre. Wolfgang Tittel and colleagues conducted their test in Calgary, Canada, but used photons at both a telecommunication wavelength and a wavelength of 795 nm, which allowed their quantum teleportation experiment to run faster than Zhang, Pan and colleagues’ experiment, but at a reduced fidelity.

In an accompanying News & Views article, Frederic Grosshans writes: “Combined, these two experiments clearly show that teleportation across metropolitan distances is technologically feasible, and undoubtedly many interesting quantum information experiments in the future will be built on this work.”

doi: 10.1038/nphoton.2016.179


メールマガジンリストの「Nature 関連誌今週のハイライト」にチェックをいれていただきますと、毎週各ジャーナルからの最新の「注目のハイライト」をまとめて皆様にお届けいたします。