Qubit cross talk and entanglement decay

We study the decohering effect of qubit-qubit interactions on entanglement. Modeling such qubit cross talk by nearest-neighbor exchange interactions, we explore the Heisenberg spin chain as a system in which decoherence occurs dynamically, and we obtain an analytic description of the process. We find expressions for the short-time and long-time transfer and decay of entanglement in a long chain, and examine the role of entanglement propagation as a decoherence mechanism.