Abstract
We investigate a new numerical procedure to compute
fermionic correlation functions at very small quark masses. Large
statistical fluctuations, due to the presence of local ``bumps'' in
the wave functions associated with the low-lying eigenmodes of the
Dirac operator, are reduced by an exact low-mode averaging. To
demonstrate the feasibility of the technique, we compute the
two-point correlator of the left-handed vector current with
Neuberger fermions in the quenched approximation, for lattices with
a linear extent of L ≈ 1.5 fm, a lattice spacing a ≈ 0.09 fm, and quark masses down to the 
-regime. By
matching the results with the corresponding (quenched) chiral
perturbation theory expressions, an estimate of (quenched)
low-energy constants can be obtained. We find agreement between the
quenched values of F extrapolated from the p-regime and
extracted in the -regime.
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