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Title: Quantum Teleportation Between Photons From Two Distant Light Sources
Achieved

Link: https://science.slashdot.org/story/25/11/20/0...

Researchers in Germany achieved a major milestone for the future quantum
internet by successfully teleporting quantum information between photons
generated by two different, physically separated quantum dots -- something
never accomplished before due to the difficulty of producing
indistinguishable photons from remote sources. Phys.org reports: At the
University of Stuttgart, the team succeeded in teleporting the polarization
state of a photon originating from one quantum dot to another photon from a
second quantum dot. One quantum dot generates a single photon, the other an
entangled photon pair. Entangled means that the two particles constitute a
single quantum entity, even when they are physically separated. One of the
two particles travels to the second quantum dot and interferes with its light
particle. The two overlap. Because of this superposition, the information of
the single photon is transferred to the distant partner of the pair.
Instrumental for the success of the experiment were quantum frequency
converters, which compensate for residual frequency differences between the
photons. These converters were developed by a team led by Prof. Christoph
Becher, an expert in quantum optics at Saarland University. [...] In the
Stuttgart experiment, the quantum dots were separated only by an optical
fiber of about 10 m length. "But we are working on achieving considerably
greater distances," says Strobel. In earlier work, the team had shown that
the entanglement of the quantum dot photons remains intact even after a 36-
kilometer transmission through the city center of Stuttgart. Another aim is
to increase the current success rate of teleportation, which currently stands
at just over 70%. Fluctuations in the quantum dot still lead to slight
differences in the photons. The findings have been published in the journal
Nature Communications.

Read more of this story at Slashdot.

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