Quantum teleportation of a particle of light six kilometers – ‘Captain Kirk to Enterprise – Beam Us Up’


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Distance record set for teleporting a photon over a fiber network

A group of physicists led by Wolfgang Tittel have successfully demonstrated teleportation of a photon, an elementary particle of light, over a straight-line distance of six kilometres.
Credit: Riley Brandt, University of Calgary

What if you could behave like the crew on the Starship Enterprise and teleport yourself home or anywhere else in the world? As a human, you’re probably not going to realize this any time soon; if you’re a photon, you might want to keep reading.

Through a collaboration between the University of Calgary, The City of Calgary and researchers in the United States, a group of physicists led by Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary have successfully demonstrated teleportation of a photon (an elementary particle of light) over a straight-line distance of six kilometres using The City of Calgary’s fibre optic cable infrastructure. The project began with an Urban Alliance seed grant in 2014.

This accomplishment, which set a new record for distance of transferring a quantum state by teleportation, has landed the researchers a spot in the journal Nature Photonics. The finding was published back-to-back with a similar demonstration by a group of Chinese researchers.

“Such a network will enable secure communication without having to worry about eavesdropping, and allow distant quantum computers to connect,” says Tittel.

Experiment draws on ‘spooky action at a distance’

The experiment is based on the entanglement property of quantum mechanics, also known as “spooky action at a distance” — a property so mysterious that not even Einstein could come to terms with it.

“Being entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,” explains Tittel. “When one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the University of Calgary.” teleportation-091916-7853834-3x2-700x467

Next, the photon whose state was teleported to the university was generated in a third location in Calgary and then also travelled to City Hall where it met the photon that was part of the entangled pair.

“What happened is the instantaneous and disembodied transfer of the photon’s quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres away at the university,” says Tittel.

City’s accessible dark fibre makes research possible

The research could not be possible without access to the proper technology. One of the critical pieces of infrastructure that support quantum networking is accessible dark fibre. Dark fibre, so named because of its composition — a single optical cable with no electronics or network equipment on the alignment — doesn’t interfere with quantum technology.

The City of Calgary is building and provisioning dark fibre to enable next-generation municipal services today and for the future.

“By opening The City’s dark fibre infrastructure to the private and public sector, non-profit companies, and academia, we help enable the development of projects like quantum encryption and create opportunities for further research, innovation and economic growth in Calgary,” said Tyler Andruschak, project manager with Innovation and Collaboration at The City of Calgary.

“The university receives secure access to a small portion of our fibre optic infrastructure and The City may benefit in the future by leveraging the secure encryption keys generated out of the lab’s research to protect our critical infrastructure,” said Andruschak. In order to deliver next-generation services to Calgarians, The City has been increasing its fibre optic footprint, connecting all City buildings, facilities and assets.

Timed to within one millionth of one millionth of a second

As if teleporting a photon wasn’t challenging enough, Tittel and his team encountered a number of other roadblocks along the way.

Due to changes in the outdoor temperature, the transmission time of photons from their creation point to City Hall varied over the course of a day — the time it took the researchers to gather sufficient data to support their claim. This change meant that the two photons would not meet at City Hall.

“The challenge was to keep the photons’ arrival time synchronized to within 10 pico-seconds,” says Tittel. “That is one trillionth, or one millionth of one millionth of a second.”

Secondly, parts of their lab had to be moved to two locations in the city, which as Tittel explains was particularly tricky for the measurement station at City Hall which included state-of-the-art superconducting single-photon detectors developed by the National Institute for Standards and Technology, and NASA’s Jet Propulsion Laboratory.

“Since these detectors only work at temperatures less than one degree above absolute zero the equipment also included a compact cryostat,” said Tittel.

Milestone towards a global quantum Internet

This demonstration is arguably one of the most striking manifestations of a puzzling prediction of quantum mechanics, but it also opens the path to building a future quantum internet, the long-term goal of the Tittel group.


Story Source:

Materials provided by University of Calgary. Original written by Drew Scherban, University Relations. Note: Content may be edited for style and length.


Journal References:

  1. Raju Valivarthi, Marcel.li Grimau Puigibert, Qiang Zhou, Gabriel H. Aguilar, Varun B. Verma, Francesco Marsili, Matthew D. Shaw, Sae Woo Nam, Daniel Oblak, Wolfgang Tittel. Quantum teleportation across a metropolitan fibre network. Nature Photonics, 2016; DOI:10.1038/nphoton.2016.180
  2. Qi-Chao Sun, Ya-Li Mao, Si-Jing Chen, Wei Zhang, Yang-Fan Jiang, Yan-Bao Zhang, Wei-Jun Zhang, Shigehito Miki, Taro Yamashita, Hirotaka Terai, Xiao Jiang, Teng-Yun Chen, Li-Xing You, Xian-Feng Chen, Zhen Wang, Jing-Yun Fan, Qiang Zhang, Jian-Wei Pan. Quantum teleportation with independent sources and prior entanglement distribution over a network. Nature Photonics, 2016; DOI:10.1038/nphoton.2016.179
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“Beam Me Up Scotty” ~ Teleportation of light particles across cities in China and Canada a ‘technological breakthrough’!


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Scientists have shown they can teleport matter across a city, a development that has been hailed as “a technological breakthrough”.

However, do not expect to see something akin to the Star Trek crew beaming from the planet’s surface to the Starship Enterprise. star-trek-transporter-1280jpg-883390_1280w

Instead, in the two studies, published today in Nature Photonics, separate research groups have used quantum teleportation to send photons to new locations using fibre-optic communications networks in the cities of Hefei in China and Calgary in Canada.

Quantum teleportation is the ability to transfer information such as the properties or the quantum state of an atom — its energy, spin, motion, magnetic field and other physical properties — to another location without travelling in the space between.

Key points

  • Two experiments demonstrate teleportation of particles across real optical fibre networks for first time
  • Chinese experiment transports two photons per hour across seven kilometres
  • Canadian experiment transports 17 photons per minute across 6.2 kilometres

 

While it was first demonstrated in 1997, today’s studies are the first to show the process is technologically possible via a mainstream communications network.

The development could lead to future city-scale quantum technologies and communications networks, such as a quantum internet and improved security of internet-based information.

Dr. Ben Buchler, Associate Professor with the Centre for Quantum Computation and Communication Technology at the Australian National University, said the technical achievement of completing the experiments in a “non-ideal environment” was “pretty profound”.

“People have known how to do this experiment since the early 2000s, but until these papers it hasn’t been performed in fibre communication networks, in situ, in cities,” said Dr. Buchler, who was not involved in the research.

“It’s seriously difficult to do what they have done.”

Watch the YouTube Video: “The Metaphysics of Teleportation” – Dr. Michio Kaku

 

A cornerstone of quantum teleportation is quantum entanglement, where two particles are intimately linked to each other in such a way that a change in one will affect the other.

Dr. Buchler said quantum teleportation involved mixing a photon with one branch of the entanglement and this joint element was then measured. The other branch of the entanglement was sent to the receiving party or new location.

This original ‘joint’ measurement is sent to the receiver, who can then use that information to manipulate the other branch of the entanglement.

“The thing that pops out is the original photon, in a sense it has indistinguishable characteristics from the one you put in,” Dr Buchler said.

Overcoming technical barriers

He said both teams had successfully overcome technical barriers to ensure the precise timing of photon arrival and accurate polarisation within the fibres.

The Chinese team teleported single protons using the standard telecommunications wavelength across a distance of seven kilometres, whiled the Canadian team teleported single photons up to 6.2 kilometres.

But work remained to increase the speed of the system with the Chinese group teleporting just two photons per hour and the Canadians a faster rate of 17 photons per minute.

Dr. Buchler said the speeds meant the development had little immediate practical value, but “this kind of teleportation is part of the protocol people imagine will be able to extend the range of quantum key distribution” — a technique used to send secure encrypted messages.

In the future scientists envision the evolution of a quantum internet that would allow the communication of quantum information between quantum computers.

Quantum computers on their own would allow fast computation, but networked quantum computers would be more powerful still.

Dr. Buchler said today’s studies were a foundation stone toward that vision as it showed it was possible to move quantum information from one location to another within mainstream networks without destroying it.

Yes … a LOT more work has to be done however before we “Warp” and “Beam” … but to put it into the words of ‘The Good Doctor’ …

“Damit Jim, I’m ONLY a doctor!” (Highly Logical) “Live long and Prosper!”

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