Dawn of solid-state quantum networks – The Holy Grail of quantum information sciences

Researchers demonstrated high-visibility quantum interference between two independent semiconductor quantum dots — an important step toward scalable quantum networks, according to January 3 article in SciTechDaily summarized below by Quantum News Briefs.
A large-scale and fully functional quantum network is the holy grail of quantum information sciences. It will open a new frontier of physics, with new possibilities for quantum computation, communication, and metrology.  Related: Click here for details for IQT The Hague March 13-15 Europe’s Quantum Communications and Quantum Security Event.
A high-performance quantum network requires not only ultra-low-loss quantum channels and quantum memory, but also high-performance quantum light sources. There has been exciting recent progress in satellite-based quantum communications and quantum repeaters, but a lack of suitable single-photon sources has hampered further advances.
As reported in Advanced Photonics, an international team of researchers has achieved high-visibility quantum interference between two independent quantum dots linked with ~300 km optical fibers. They report efficient and indistinguishable single-photon sources with ultra-low-noise, tunable single-photon frequency conversion, and low-dispersion long fiber transmission. The single photons are generated from resonantly driven single QDs deterministically coupled to microcavities. Quantum frequency conversions are used to eliminate the QD inhomogeneity and shift the emission wavelength to the telecommunications band. The observed interference visibility is up to 93%. According to senior author Chao-Yang Lu, professor at the University of Science and Technology of China (USTC), “Feasible improvements can further extend the distance to ~600 km.” Lu further remarks, “Our work jumped from the previous QD-based quantum experiments at a scale from ~1 km to 300 km, two orders of magnitude larger, and thus opens an exciting prospect of solid-state quantum networks.” With this reported jump, the dawn of solid-state quantum networks may soon begin breaking toward day.  Click here to read article in-entirety.


University Of Amsterdam receives quantum technology grant

Prof. Wybren Jan Buma of Molecular Photonics at the Van ‘t Hoff Institute for Molecular Sciences will take part in research using the new Dutch quantum supercomputer. Together with Prof. Luuk Visscher of Theoretical Chemistry at VU University, he has just been granted funding through the National Growth Fund programme Quantum Technology, for the quantum simulation of molecular mirror images.
The Dutch quantum supercomputer is located in Delft and is shared with other researchers in the Quantum Delta. The researchers will also use powerful supercomputers elsewhere in the world.
The new Dutch quantum supercomputer will be put to the task of determining the correct molecular mirror image. Just like with people, we have that the mirror image of a molecule looks almost identical but still is crucially different: Imagine putting your right hand in a left-hand glove! For molecules this may imply the difference between an effective drug and a potentially dangerous substance. The researchers in this project aim to develop a combination of measurement and quantum simulations which can unambiguously determine whether we have the desired molecule and not its mirror image.
Visscher leads the modelling work, Buma the experimental validation. As Visscher explains: ”The molecules are subjected to a thorough experimental characterization, which produces a unique ‘molecular signature’. We then use the supercomputer to calculate all possible signatures and compare those with the measured signature, to find the best match”.  Click here to read original article in-entirety.


Sandra K. Helsel, Ph.D. has been researching and reporting on frontier technologies since 1990.  She has her Ph.D. from the University of Arizona.