Nonlocal and quasi-local field theories

Understand

We investigate nonlocal field theories, a subject that has attracted some renewed interest in connection with nonlocal gravity models.

• We study, in particular, scalar theories of interacting delocalized fields, the delocalization being specified by nonlocal integral kernels.
• We distinguish between strictly nonlocal and quasi-local (compact support) kernels and impose conditions on them to insure UV finiteness and unitarity of amplitudes.
• We study the classical initial value problem for the partial integro-differential equations of motion in detail.