Generalized GHZ states and distributed quantum computing
Anocha Yimsiriwattana, Samuel J. Lomonaco · Contemporary mathematics - American Mathematical Society · 2005
A key problem in quantum computing is finding a viable techno- logical path toward the creation of a scalable quantum computer. One possible approach toward solving part of this problem is distributed computing, which provides an effective way of utilizing a network of limited capacity quantum computers. In this paper, we present two primitive operations, cat-entangler and cat- disentangler, which in turn can be used to implement non-local operations, e.g. non-local CNOT and quantum teleportation. We also show how to establish an entangled pair, and use entangled pairs to efficiently createa generalized GHZ state. Furthermore, we present procedures which allow us to reuse channel qubits in a sequence of non-local operations. These non-local operations work on the principle that a cat-like state, created by cat-entangler, can be used to distribute a control qubit among mul- tiple computers. Using this principle, we show how to efficiently implement non-local control operations in many situation, including a parallel implemen- tation of a certain kind of unitary transformation. Finally, as an example, we present a distributed version of the quantum Fourier transform.