Exploiting quench dynamics in spin chains for distant entanglement and quantum communication

Abstract

We suggest a method of entangling significantly the distant ends of a spin chain using minimal control. This entanglement between distant individual spins is brought about solely by exploiting the dynamics of an initial mixed state with N\'eel order if the lattice features nearest-neighbor $XXZ$ interaction. There is no need to control single spins or to have engineered couplings or to pulse globally. The method only requires an initial nonadiabatic switch (a quench) between two Hamiltonians followed by an evolution under the second Hamiltonian. The scheme is robust to randomness of the couplings as well as the finiteness of an appropriate quench and could potentially be implemented in various experimental setups, ranging from atoms in optical lattices to Josephson-junction arrays.