An alternative model for tunneling processes, based on the capability of the telegrapher’s equation to describe stochastic processes, is able to account for delay time results of an optical experiment at the microwave scale, where superluminal behaviors have been evidenced.
A stochastic model for tunneling processes that is based on a close correspondence between quantum relativistic and telegrapher's equations is proposed along the lines of a procedure similar to the one already adopted by Kac [Rocky Mountain J. Math 4, 497 (1974)]. It is hypothesized that reversals of motion imply the inversion of the (imaginary) time rather than of the space, as in the ordinary allowed processes. In this way, superluminal behavior can be predicted in limiting cases. The plausibility of the superluminal motions observed is then discussed on the basis of a signal analysis along the lines of the Sommerfeld-Brillouin criterion which has been suitably modified.
Delay time results obtained in microwave experiments at frequencies above and below the cutoff frequency of different waveguide sections are interpreted on the basis of wave propagation in the presence of dissipative effects. Kac's original suggestion was the starting point for the formulation of a stochastic model, which has now been substantially improved, also in relation to the transition-elements theory of Feynman-Hibbs. In this way, an approach to the problem is provided, which is completely distinct from the ones formulated elsewhere.
An alternative model for near-field propagation and optical tunneling is proposed following the lines of the path-integral method developed by Feynman, and in particular by using a transition-elements analysis. Such a model was able to account for the frequency dependency of delay-time results of an experiment involving microwave propagation in the near field using two horn antennas [A. Ranfagni et al., Phys. Rev. E 66, 036111 (2002)]. Furthermore, this approach is also capable of interpreting delay-time results as a function of the barrier width in a frustrated total internal reflection experiment performed at the microwave scale and in the optical region.