  Tunneling, transport of particles through classically forbidden regions, is a
pure quantum phenomenon. It governs numerous phenomena ranging from
single-molecule electronics to donor-acceptor transition reactions. The main
problem is the absence of a universal method to compute tunneling time. This
problem has been attacked in various ways in the literature. Here, in the
present work, we show that a statistical approach to the problem, motivated by
the imaginary nature of time in the forbidden regions, lead to a novel
tunneling time formula which is real and subluminal (in contrast to various
known time definitions implying superluminal tunneling). This entropic
tunneling time, as we call it, shows good agreement with the tunneling time
measurements in laser-driven He ionization. Moreover, it sets an accurate range
for long-range electron transfer reactions. The entropic tunneling time is
general enough to extend to the photon and phonon tunneling phenomena.
