Category:Entanglement Distribution Network stage

The third network stage, entanglement distribution allows shared entanglement i.e. two nodes can be connected using entanglement. It could be further used to share states between two nodes without physically transferring the qubits over quantum channels. Yet this feature cannot be completely put in use unless one can store quantum states which is only possible with quantum memory, not a technology accessible at this network stage. It includes all the prepare and measure network stage technologies along with sharing of entanglement between two nodes separated by some distance. Post-selection on detection events when measuring qubits is prohibited.

Applications and Features[edit]

The main advantage over the previous stages (Trusted Repeater and Prepare and Measure) is that this stage allows the realization of device independent protocols, in which the quantum devices are largely untrusted. It also allows generation of multipartite entangled states, followed by immediate measurements.

The network stage includes two types of end-to-end (shared between two nodes) entanglement, deterministic and heralded. Deterministic entanglement refers to the fact that the process succeeds with (near) unit probability while heralding is a slightly weaker form of deterministic entanglement distribution in which the successful generation of entanglement is signaled with an event that is independent of the (immediate) measurement of the entangled qubit.

Relevant Parameters[edit]

• Distances ${\displaystyle \epsilon _{P}}$ from the ideal preparation, and ${\displaystyle \epsilon _{M}}$ from the idealized measurement. These distances are diamond norm distance between the states obtained from ideal preparation, measurement and real (noisy) preparation and measurement.