Suppression of arbitrary internal coupling in a quantum register
Marcus Stollsteimer, Günter Mahler · Physical Review A · 2001
For the implementation of a quantum computer it is necessary to exercise complete control over the Hamiltonian of the used physical system. For nuclear magnetic resonance quantum computing the effectively acting Hamiltonian can be manipulated via pulse sequences. Here we examine a register consisting of N selectively addressable spins with pairwise coupling between each spin pair. We show that complete decoupling of the spins is possible, independent of the particular form of the spin-spin interaction. The proposed method based on orthogonal arrays is efficient in the sense that the effort regarding time and amount of pulses increases only polynomially with the size N of the register. However, the effect of external control errors in terms of inaccurate control pulses eventually limits the achievable precision.