A collaboration between the Universities of Hong-Kong, Grenoble and Vienna, as well as the Austrian Academy of Sciences has revealed novel techniques to reduce noise in quantum communication.
The primary approach to overcome these noise limitations is the application of so-called quantum error-correcting codes. This, however, requires an amount of resources exceeding that which can be currently achieved in a controlled way. While, in the long run, error correction is likely to become an integral part of future quantum devices, a complementary approach is to mitigate the noise —that is, the cumulative effect of uncorrected errors— without relying on so many additional resources. These are referred to as noise reduction schemes.
To achieve this noise reduction, it is now known that it is necessary to place the noisy transmission lines in a quantum superposition of opposite orders. The team of researchers realized that this effect can also be achieved via simpler configurations, which can even completely eliminate the noise between two parties.
Surprisingly, it is found that the simplest schemes for quantum superposition of noisy channels also offer the best reduction of the noise affecting communication. (Phys.org)
The results has been published in Physical Review Research.