He, along with the other theoretical Physics professors at Berkeley, refused to sign the McCarthy era loyalty oath on principle, and in 1950 went to Princeton to work for Bell Labs where he did research on superconducting materials.
He, along with the other theoretical Physics professors at Berkeley, refused to sign the McCarthy era loyalty oath on principle, and in 1950 went to Princeton. Later, when offered reinstatement at Berkeley, he chose instead to accept a position at Bell Labs where he did research on superconducting materials.