1.A Feynman propagator is constructed for the effective interaction between electrons which takes into account the polarizability of the medium of unexcited particles in the Fermi sea.
2.He was still unexcited. Most unusual, he thought. It was probably a trick of his mind. He was certain of this when he also saw a ship floating in the shining sea.
3.On the other hand, the scout was obscure; because from the lingering pride of color, he rather affected the cold and artificial manner which characterizes all classes of Anglo-Americans when unexcited.