Fast incomplete, decoherence of nuclear spins in a quantum Hall ferromagnet - art. no. 193306

A scenario of the quantum computing process based on the manipulation of a large number of nuclear spins in quantum Hall (QH) ferromagnets is presente d. It is found that vacuum quantum fluctuations in the QH ferromagnetic gro und state at filling factor nu =1, associated with the virtual excitations of spin waves, lead to fast incomplete decoherence of the nuclear spins. A fundamental constraint on the level of decoherence is set by this fluctuati on effect. For GaAs multiple-quantum-well structures we find a coherence le vel not smaller than 1-10(-9), which is safely above the danger level of qu antum error correction methods.