  The fermionic Ising spin glass models in a transverse field are investigated
in a Grassmann path integral formalism. The Parisi's scheme of one-step replica
symmetry breaking (RSB) is used within the static ansatz. This formalism has
already been applied in a theory in which $m$ (Parisi's block-size parameter)
is taken as a constant (PRB 72, 014447 (2005)). Now, it is extended to consider
$m$ as a variational parameter. In this case, the results show that RSB is
present when $T\to0$, in which the system is driven by quantum fluctuations.

Strongly Correlated Electrons;Disordered Systems and Neural Networks