DUAL SUPERCONDUCTIVITY IN THE SU(2) PURE GAUGE VACUUM - A LATTICE STUDY

We investigate the dual superconductivity hypothesis in pure SU(2) lat tice gauge theory. We focus on the dual Meissner effect by analyzing t he distribution of the color fields due to a static quark-antiquark pa ir. We find evidence of the dual Meissner effect both in the maximally Abelian gauge and without gauge fixing. We measure the London penetra tion length. Our results suggest that the London penetration length is a physical gauge-invariant quantity. We put out a simple relation bet ween the penetration length and the square root of the string tension. We find that our estimation is quite close to the extrapolated contin uum limit available in the literature. A remarkable consequence of our study is that an effective Abelian theory can account for the long ra nge properties of the SU(2) confining vacuum.