Anomalies and Deconfinement

I discuss how instanton effects can be wiped-out due to the existence of anomalies. I first consider Compact Quantum Electrodynamics in 3 dimensions where confinement of electric charge is destroyed when fermions are added so that a Chern-Simons term is generated as a one-loop effect. I also show that a similar phenomenon occurs in the two-dimensional abelian chiral Higgs model. In both cases anomalies (parity anomaly, gauge anomaly) are responsible of the deconfinement mechanism.