Three-Body Bound States and the Development of Odd-Frequency Pairing

We propose that the development of odd-frequency superconductivity is driven by the growth of an anomalous three-body scattering amplitude. Using this as an ansatz we develop a mean-field theory for odd-frequency pairing within the Kondo lattice model. The three-body bound-state formation leads to the formation of a gapless band of strongly paired quasiparticles whose spin and charge coherence factors vanish linearly with energy. Possible links with heavy fermion superconductors are discussed.