  We present an estimate of the nuclear electric polarizability of the 6He halo
nucleus based on six-body microscopic calculations. Wave functions are obtained
from semi-realistic two-body interactions using the hyperspherical harmonics
expansion method. The polarizability is calculated as a sum rule of the dipole
response function using the Lanczos algorithm and also by integrating the
photo-absorption cross section calculated via the Lorentz integral transform
method. We obtain alpha_E=1.00(14) fm^3, which is much smaller than the
published value 1.99(40) fm^3 extracted from experimental data. This points
towards a potential disagreement between microscopic theories and experimental
observations.
