Quan­tum Tele­por­ta­ti­on across Saar­brü­cken

Rese­ar­chers from Saar­land Uni­ver­si­ty (UdS) have achie­ved an important breakth­rough in Quan­tum Com­mu­ni­ca­ti­on by demons­t­ra­ting Quan­tum Ent­an­gle­ment and Tele­por­ta­ti­on over a 14 km long fiber link, the “Saar­brü­cken Quan­tum Com­mu­ni­ca­ti­on Fiber Test­bed”. The phy­si­cists, led by the pro­fes­sors Dr. Jür­gen Esch­ner and Dr. Chris­toph Becher, used pho­ton pairs in which the sta­tes of two light par­tic­les are ent­an­gled, i.e. their sta­tes are ran­dom but always cor­re­la­ted. One of the ent­an­gled pho­tons is trans­mit­ted via the opti­cal fiber to the Uni­ver­si­ty of Appli­ed Sci­en­ces (htw), while the other inter­acts with a sin­gle atom in the UdS lab. This inter­ac­tion enables the sta­te of the atom to be tele­por­ted to the pho­ton at the htw – a remar­kab­le step for future quan­tum com­mu­ni­ca­ti­on net­works. The results of the expe­ri­ment have now been published in a paper. In addi­ti­on, the Saar­län­di­sche Rund­funk (SR) picked up on this remar­kab­le pro­gress in Quan­tum Rese­arch in its “aktu­el­ler bericht” on 8 Octo­ber 2024 (from minu­te 22:50).

A spe­cial chall­enge was that the fiber link runs part­ly abo­ve ground and is the­r­e­fo­re expo­sed to exter­nal influen­ces such as wind and wea­ther, which makes it dif­fi­cult to trans­mit infor­ma­ti­on on the sen­si­ti­ve light par­tic­les. To over­co­me this, the sci­en­tists con­ti­nuous­ly mea­su­red and com­pen­sa­ted for poten­ti­al inter­fe­rence. This makes the results of the expe­ri­ment par­ti­cu­lar­ly valuable, as they show that Quan­tum Com­mu­ni­ca­ti­on is pos­si­ble even under dif­fi­cult con­di­ti­ons. The rese­ar­chers are now plan­ning to use Quan­tum Ent­an­gle­ment to crea­te Quan­tum Keys for secu­re infor­ma­ti­on trans­mis­si­on. In addi­ti­on, the Saar­brü­cken test­bed is to beco­me part of a Ger­ma­ny-wide Quan­tum Net­work that will be used for secu­re com­mu­ni­ca­ti­on and data exch­an­ge bet­ween Quan­tum Com­pu­ters. Click here for fur­ther infor­ma­ti­on on the publi­ca­ti­on of the paper.

Illus­tra­ti­on: Cour­se of the approx. 14.4 kilo­me­ter long fiber link exten­ding from Saar­land Uni­ver­si­ty (UdS) to the Uni­ver­si­ty of Appli­ed Sci­en­ces (htw) in Saar­brü­cken. Under­ground sec­tions are shown in red and over­head sec­tions in blue (map data: © Open­Street­Map).

Aut­hor of the illus­tra­ti­on: © Uni­ver­si­tät des Saar­lan­des

Source refe­rence: https://www.uni-saarland.de/aktuell/quanten-teleportation-34247.html