ar X iv : h ep - t h / 96 10 18 3 v 1 2 3 O ct 1 99 6 GROUP CONTRACTIONS : INONU , WIGNER , AND EINSTEIN
نویسنده
چکیده
Einstein's E = mc 2 unifies the momentum-energy relations for massive and massless particles. According to Wigner, the internal space-time symmetries of massive and massless particles are isomorphic to O(3) and E(2) respectively. According to Inonu and Wigner, O(3) can be contracted to E(2) in the large-radius limit. It is noted that the O(3)-like little group for massive particles can be contracted to the E(2)-like little group for massless particles in the limit of large momentum and/or small mass. It is thus shown that transverse rotational degrees of freedom for massive particles become contracted to gauge degrees of freedom for massless particles.
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