State transferring through spin chains

IICQI 2007
Talk type: 

It's predicted that the quantum computers will be built by the solid state technology. So in that dimension communication between different nodes is very important and hard technologically. Thus sending the states by natural time evolution of a chain of spins has been interested during these recent years. In this scheme a quantum state is generated at the first site of the ferromagnetic chain and by time evolution of the system the state of the last site will be similar to the initial state. In the algorithm the ferromagnetic system is generated in its ground state which means that we should use zero temperature to run this algorithm but here we have studied the effect of nonzero but low temperature on the quality of state transferring. Another problem that is considered here is entanglement distribution, which means that we generate an entangled pair at the start of the chain and we keep one particle out of the chain and the other is sent through the chain and it can be shown that the entanglement between the noninteracting particle and the last site of the chain has a significant value. As another problem we have investigated the dependence of the state transferring on the dimension of Hilbert space of each site in the chain. The results show that the quality of state transferring comes dawn by increasing the dimension and saturates a specific value. In contrast in the case of entanglement distribution the efficiency is increased for higher dimensions.