About the project

Transfer of quantum superposition states across long distances has the potential to add significant capabilities in the information age. One of the first applications will be quantum cryptographic key distribution, which can be used to ensure completely secure communications.

 

The maximum distances possible for quantum communications are currently limited by photon losses due to absorption in the optical fibres fibres used to transmit the signal. The no-cloning theorem which guarantees secure quantum key distribution means that traditional amplifiers used to overcome absorption losses cannot be used.

 

Instead, by concatenating short entanglement swapping sub-sections it is in principle possible to generate entangled (correlated) bits over very long distances with bit rate only limited by the losses in one short section. If realised this would extend quantum communication applications such as quantum cryptography and quantum teleportation out to distances of thousands of kilometres.

 

In this consortium we are working towards such a deterministic quantum network based on semiconductor quantum dot-micropillar cavity systems. We are developing the following main components:

  • 'quantum repeaters'
  • deterministically generated entangled photon pair sources
  • electro-optically tuneable single photon sources
  • sequentially entangled sources

 

With this suite of components we will be able to realise all the functions required for a scalable quantum network including the final entanglement purification steps.