Anomaly and Thermodynamics for 2D Spinors in the Aharonov--Bohm Gauge   Field
  The axial anomaly is computed for Euclidean Dirac fermions on the plane. The dependence upon the self-adjoint extensions of the Dirac operator is investigated and its relevance concerning the second virial coefficient of the anyon gas is discussed. 
P. Giacconi, F. Maltoni and R. Soldati