We consider a quantum system consisting of four subsystems (Aa, Bb). The Aa location is prepared entangled with the Bb location. We show how to generate entanglement between two remote sites by purely local interactions.
We address the problem of the generation of entanglement. We focus on the control of entanglement shared by two non-interacting parties A and C via interaction with a third party B. We show that, for certain physical models, it is possible to have an asymptotically complete control of the entanglement shared by A and C by changing parameters of the Hamiltonian local at site B. We present an example where different models (propositions) of physical situation, that lead to different descriptions of the system B, result into different amount entanglement produced. In the end we discuss limits of the procedure.
We suggest two schemes to generate bipartite entangled states by means of a quantum measurement at a third party. The two parties to be entangled have separate entangled states with the third party in modes C1 and C2. In our first scheme we generate entanglement between the two remote parties by considering the modes C1 and C2 indistinguishable. However, in the second scheme we generate entangled states by considering the two modes to be distinguishable. We discuss that the first scheme of remote entanglement generation can be extended to any N number of parties. On making a quantum measurement on this system, we develop quantum networks, based on W-states and other multipartite symmetric entangled states. 1
We examine entanglement dynamics via concurrence among four two-state systems labelled A , a , B , b . The four systems are arranged on an addressable 'lattice' in such a way that A and a at one location labelled Aa can interact with each other via excitation exchange, and the same for B and b at location Bb . The Aa location is prepared entangled with the Bb location, but their mutual complete isolation prevents interaction in the interval between actions of an external addressing agent. There are six pairwise concurrences on the lattice, and we follow their evolution in the interval between external actions. We show how entanglement evolves and may exhibit the non-analytic effect termed entanglement sudden death (ESD), with periodic recovery. These loss and gain processes may be interpreted as entanglement transfers between the subsystems.
We propose a deterministic remote state preparation scheme for photon polarization qubit states, where entanglement, local operations, and classical communication are used. By consuming one maximally entangled state and two classical bits, an arbitrary (either pure or mixed) qubit state can be prepared deterministically at a remote location. We experimentally demonstrate the scheme by remotely preparing 12 pure states and 6 mixed states. The fidelities between the desired and achieved states are all higher than 0.99 and have an average of 0.9947.