  Quantum network communication is challenging, as the No-cloning theorem in
quantum regime makes many classical techniques inapplicable. For long-distance
communication, the only viable communication approach is teleportation of
quantum states, which requires a prior distribution of entangled pairs (EPs) of
qubits. Establishment of EPs across remote nodes can incur significant latency
due to the low probability of success of the underlying physical processes.
  The focus of our work is to develop efficient techniques that minimize EP
generation latency. Prior works have focused on selecting entanglement paths;
in contrast, we select entanglement swapping trees--a more accurate
representation of the entanglement generation structure. We develop a dynamic
programming algorithm to select an optimal swapping-tree for a single pair of
nodes, under the given capacity and fidelity constraints. For the general
setting, we develop an efficient iterative algorithm to compute a set of
swapping trees. We present simulation results which show that our solutions
outperform the prior approaches by an order of magnitude and are viable for
long-distance entanglement generation.
