R. Laflamme et al., NMR GREENBERGER-HORNE-ZEILINGER STATES, Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences, 356(1743), 1998, pp. 1941-1947
We describe the creation of a Greenberger-Horne-Zeilinger state of the
form (\000] + \111])/ root 2 (three maximally entangled quantum bits)
using nuclear magnetic resonance. We have successfully carried out th
e experiment using the proton and carbon spins of trichloroethylene, a
nd confirmed the result using state tomography. We have thus extended
the space of entangled quantum states explored systematically to three
quantum bits, an essential step for quantum computation.