Nonperturbative tunneling under a rank-two field

Determine whether a static or slowly varying rank-two field can support a genuinely nonperturbative tunneling regime associated with the field work required to separate oppositely oriented dipoles.

Background

The paper establishes multiphoton dipole–antidipole production from a Mott background under a periodically driven rank-two electric field. Exact dipole conservation changes the produced mobile objects from ordinary opposite charges to oppositely oriented dipoles, and the field energy contains a term proportional to the separation of those dipoles at fixed internal dipole size.

The authors explicitly distinguish their periodically driven, perturbative multiphoton analysis from a nonperturbative constant-field Schwinger process. They identify the possibility that a static or slowly varying rank-two field could induce tunneling governed by the work required to separate the dipoles, but they do not derive the corresponding tunneling law, WKB/instanton description, or Schwinger-like exponent.