Leib­niz uni­ver­si­tät Han­no­ver (LUH)

Quan­tum Com­mu­ni­ca­ti­on is one of the most pro­mi­sing tech­no­lo­gies of our time. It pro­mi­ses the theo­re­ti­cal­ly com­ple­te secu­re encryp­ti­on of mes­sa­ges, regard­less the available tools of the poten­ti­al adver­sa­ry. The secu­ri­ty of Quan­tum Key Dis­tri­bu­ti­on (QKD) is based on the laws of Quan­tum Mecha­nics, which are skillful­ly exploi­ted to detect whe­ther the com­mu­ni­ca­ti­on line used for key trans­mis­si­on is being inter­cept­ed during encryp­ti­on. In addi­ti­on, Quan­tum Com­mu­ni­ca­ti­on enables the secu­re con­nec­tion of future Quan­tum Com­pu­ters at dif­fe­rent loca­ti­ons, allo­wing their com­pu­ting power to be com­bi­ned (dis­tri­bu­ted Quan­tum Com­pu­ting). Tog­e­ther, the­se aspects form the visi­on of the Quan­tum Inter­net.

The rese­arch group of Prof. Fei Ding is working on pre­cis­e­ly this visi­on: they are deve­lo­ping and test­ing so-cal­led Semi­con­duc­tor Quan­tum Dots, which will play a key role in the phy­si­cal rea­liza­ti­on of the Quan­tum Inter­net. As they can func­tion both as sin­gle pho­ton or ent­an­gle­ment sources and as Quan­tum Memo­ries, they have all the pro­per­ties requi­red for so-cal­led Quan­tum Repea­ters. The­se will enable effi­ci­ent Quan­tum Com­mu­ni­ca­ti­on over any distance and thus play a decisi­ve role in the estab­lish­ment of a Ger­ma­ny- and Euro­pe-wide Quan­tum Net­work.

On the way to this goal, they unite a com­ple­te rese­arch infra­struc­tu­re under one roof. They are part of the “Nie­der­sach­sen Quan­tum Link” fiber net­work – a fiber test­bed that con­nects seve­ral rese­arch insti­tu­ti­ons in Han­no­ver with the Phy­si­ka­lisch-Tech­ni­sche Bun­des­an­stalt (PTB) in Braun­schweig. This net­work makes it pos­si­ble to test new­ly deve­lo­ped Quan­tum Repea­ter com­pon­ents and sta­te-of-the-art QKD pro­to­cols and sys­tems effi­ci­ent­ly and rea­li­sti­cal­ly. The test­bed was recent­ly used to demons­tra­te the world’s first Quan­tum Com­mu­ni­ca­ti­on expe­ri­ment with a real semi­con­duc­tor sin­gle pho­ton source bet­ween two cities as well as quan­tum-based time and fre­quen­cy syn­chro­niza­ti­on.