In this paper we show that noncommutativity in spatial coordinates can generate magnetic field in the early Universe on a horizon scale. The strength of such a magnetic field depends on the number density of massive charged particles present at a given moment. This allows us to trace back the temperature dependence of the noncommutativity scale from the bounds on primordial magnetic field coming from nucleosynthesis.
© 2001 The American Physical Society
Revtex, 4 pages, v3: very minor changes, the version to appear in PRL