Fermion doubling and gauge invariance on random lattices.

Random-lattice fermions have been shown to be free of the doubling problem if there are no interactions or interactions of a nongauge nature. On the other hand, gauge interactions impose stringent constraints as expressed by the Ward-Takahashi identities which could revive the free-field suppressed doubler modes in loop diagrams. Comparing random-lattice, naive, and Wilson fermions in two-dimensional Abelian background gauge theory, we show that indeed the doublers are revived for random lattices in the continuum limit. Some implications of the persistent doubling phenomenon on random lattices are also discussed.