Localized Entanglement in One-dimensional Anderson Model

Entanglement is a kind of nonlocal correlation that only exists in quantum systems. Recent studies on entanglement have been motivated by its potential applications in quantum computation, quantum teleportation and quantum communication. As the spin system is perfect to realize the quantum computer, many efforts focus on the entanglement in the Heisenberg spin model, Ising model in a transverse magnetic field and itinerant fermionic systems. In the quantum computer, one needs to control and measure individual qubits. However, in many possible physical implementations of the quantum computer, the interaction between spin and spin (or qubit–qubit) is inevitable, and excitation or paticles can hop from one site to other sites. So it is hard to operate on one single qubit. To overcome this difficulty, one excitation should be pinned on a certain site. It is well known that the localization can pin the excitation. On the other hand, being a fundamental concept of quantum theory, entanglement is involved in many fields of physics. It has been shown that entanglement is a indicator of quantum phase transition.6–8 The relation between entanglement and chaos, and the relation between entanglement and localization have been discussed, and it was found that strong localization decreases entanglement. The quantum