A European team of physicists working in the lab of Professor Nicolas Gisin in the physics department at the University of Geneva, has demonstrated a method that can teleport quantum information to a solid-state quantum memory over telecom fiber.
This marks a crucial milestone towards the development of quantum Internet, for physicist Félix Bussières who has been heading the research group through a string of experiments carried out in the last decade in order to perfect quantum data transfer using entanglement.
What occurred was teleportation of the quantum state of a photon to another doped with rare-earth ions, placed at a distance of 25 kilometers, essentially transferring information from light to matter, over an ordinary telecom optical fiber in use all over the world. The previous record was of 6 kilometers (3.7 miles) set in 2003 by the same team.
To set things in perspective, Quantum teleportation is a process by which quantum data can be transmitted from one location to another, with the help of classical communication and quantum entanglement between the sending and receiving location, without traveling through the space in between. Matter itself doesn’t make this journey, only the information that describes it, explains the MIT Technology Review.
The researchers were able to generate entangled pairs of photons (suppose photon A and B) with different wavelengths, one of which passes easily through telecoms optical fiber(say photon B). So these guys send photon A, as a signal to the quantum memory (doped crystal) where it is stored, while transmitting photon B, through a fiber to another apparatus that prepares a third photon (also at the same wavelength as B, we call it X) with the polarization to be teleported.
This is when the teleportation takes place. When B and X photons interact in a certain way, the polarization is teleported to the quantum memory at the other end of the experiment, to A.
“The team’s measurements on these photons show that the polarization state is indeed teleported as quantum mechanics suggests. A crucial part of the experiment is a new generation of single photon detectors that can spot telecoms photons with much greater efficiency than has been possible before,” reports the MIT Technology Review.
This marks a small step towards the possibility of quantum internet, the kind of machinery that needs to be developed to make it happen.
The findings of the research were published in the journal Nature Photonics on September 21.
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(Image credit: University of Geneva)