  We propose that a composite fermion operator $f_{i\sigma}(2n_{i{\bar
\sigma}}-1)$ could have coherent excitations, where $f_{i\sigma}$ is the
fermion operator for interacting electrons and $n_{i{\bar \sigma}}$ is the
number operator of the opposite spin. In the two-impurity Anderson model, it is
found that the excitation of this composite fermion has a pseudogap in the
Kondo regime, and has a finite spectral weight in the regime where the
excitation of the regular fermion $f_{i\sigma}$ has a pseudogap. In the latter
regime, the self-energy of $f_{i\sigma}$ is found to be singular near Fermi
energy. We argue that this composite fermion could develop a Fermi surface with
Fermi liquid behaviors but "hidden" from charge excitations in lattice
generalizations. We further illustrate that this type of excitations is
essential in addressing the pseudogap state and unconventional
superconductivity.

Strongly Correlated Electrons;Superconductivity