Relativistic field theories in a strong magnetic background asnoncommutative field theories

The connection between the dynamics in relativistic field theories in a strong magnetic field and the dynamics of noncommutative field theories (NCFTs) is discussed. It is shown that this connection is rather sophisticated. In fact, the corresponding NCFTs are different from the conventional ones considered in the literature. In particular, the UV/IR mixing is absent in these theories. The reason for this is an inner structure (i.e., dynamical form factors) of neutral composites that plays an important role in providing consistency for NCFTs. NCFTs could find interesting applications in condensed-matter systems and string theories.