Entangling capacities of noisy two-qubit Hamiltonians
Somshubhro Bandyopadhyay, Daniel A. Lidar · Physical Review A · 2004
We study the limits imposed by intrinsic fluctuations in system-control parameters on the ability of two-qubit (exchange) Hamiltonians to generate entanglement, starting from arbitrary initial states. We find three classes for Gaussian and Laplacian fluctuations. For the Ising and $XYZ$ models there are qualitatively distinct, sharp entanglement-generation transitions, while the class of Heisenberg, $XY$, and $XXZ$ Hamiltonians is capable of generating entanglement for any finite noise level. Our findings imply that exchange Hamiltonians are surprisingly robust in their ability to generate entanglement in the presence of noise, thus potentially reducing the need for quantum error correction.