  Nuclear Generalized Parton Distributions (GPDs), a unique tool to access
several crucial features of nuclear structure, could be measured in the
coherent channel of hard exclusive processes, such as deep electroproduction of
photons and mesons off nuclear targets. Here, a realistic microscopic
calculation of the unpolarized quark GPD H_q^3 of the ^3He nucleus is
described. In Impulse Approximation, H_q^3 is shown to be given by a
convolution between the GPD of the internal nucleon and the non-diagonal
spectral function, describing properly Fermi motion and binding effects. The
obtained formula has the correct limits. Nuclear effects, evaluated by a modern
realistic potential, are found to be larger than in the forward case. In
particular, they increase with increasing the momentum transfer and the
asymmetry of the process. Besides, it is found that the nuclear GPD cannot be
factorized into a \Delta^2-dependent and a \Delta^2-independent term, as
suggested in prescriptions proposed for finite nuclei. The dependence of the
obtained GPDs on different realistic potentials used in the calculation shows
that these quantities are sensitive to the details of nuclear structure at
short distances.
