Superselection Structure of Massive Quantum Field Theories in 1+1 Dimensions
Michael Müger
May 05, 1997
We show that a large class of massive quantum field theories in 1+1
dimensions, characterized by Haag duality and the split property for wedges,
does not admit locally generated superselection sectors in the sense of
Doplicher, Haag and Roberts. Thereby the extension of DHR theory to 1+1
dimensions due to Fredenhagen, Rehren and Schroer is vacuous for such theories.
Even charged representations which are localizable only in wedge regions are
ruled out. Furthermore, Haag duality holds in all locally normal
representations. These results are applied to the theory of soliton sectors.
Furthermore, the extension of localized representations of a non-Haag dual net
to the dual net is reconsidered. It must be emphasized that these statements do
not apply to massless theories since they do not satisfy the above split
property. In particular, it is known that positive energy representations of
conformally invariant theories are DHR representations.
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