CPT-like states in an ensemble of interacting fermions. On the   possibility of new mechanism of superconductivity
  Using the standard Hamiltonian of the BCS theory, we show that in an ensemble of interacting fermions there exists a coherent state $|NC>$, which nullifies the Hamiltonian of the interparticle interaction. This state has an analogy with the well-known in quantum optics coherent population trapping effect (CPT). A possible application of such CPT-like states in the superconductivity theory is discussed. 
A.V. Taichenachev and V.I. Yudin