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Abstract:
The distribution of quantum states over long distances is essential for future applications such as quantum key distribution and quantum networks. The direct distribution of quantum states is limited by the unavoidable transmission losses due to fiber attenuation. In addition to losses, there are also operation errors such as depolarization errors that severely degrade the secure key generation rate. Depending on how loss and operation errors are suppressed, three classes of quantum repeaters have been proposed.
The first class of quantum repeaters is fairly slow (~1bit/s over 1000km) due to the time overhead to correct operation errors. The second class of quantum repeaters is much faster yet limited by the communication time between neighboring repeater stations (~Kbits/s). Recently, a third class of quantum repeaters has been proposed, which can achieve ultrafast communication rates (MHz-GHz) limited only by the local gate speed.
In this talk, I will investigate the third class of quantum repeaters and show that it can overcome both operation and loss errors and describe a way to optimize time and qubit resources for them. Although it is very challenging to demonstrate the three classes of quantum repeaters, their implementation has already triggered many exciting investigations over various physical systems, ranging from atoms to ions, and from NV impurities to quantum dots. This will lead to revolutionary development in secure quantum communication and global quantum networks.
Ref: S. Muralidharan et. al. Phys. Rev. Lett. 112, 250501
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