Theta-terms in nonlinear sigma-models
Abstract
We trace the origin of θ-terms in nonlinear σ-models as a nonperturbative anomaly of current algebras. The nonlinear σ-models emerge as a low energy limit of fermionic σ-models. The latter describe Dirac fermions coupled to chiral bosonic fields. We discuss the geometric phases in three hierarchies of fermionic σ-models in space-time dimension ( d+1) with chiral bosonic fields taking values on d-, d+1-, and d+2-dimensional spheres. The geometric phases in the first two hierarchies are θ-terms. We emphasize a relation between θ-terms and quantum numbers of solitons.
- Publication:
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Nuclear Physics B
- Pub Date:
- March 2000
- DOI:
- 10.1016/S0550-3213(99)00820-2
- arXiv:
- arXiv:hep-th/9911025
- Bibcode:
- 2000NuPhB.570..685A
- Keywords:
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- High Energy Physics - Theory;
- Condensed Matter;
- High Energy Physics - Phenomenology
- E-Print:
- 10 pages, no figures, revtex, typos corrected