  Achieving electrical conductance in amorphous non-doped polymers is a
challenging task. Here, we show that vibrational strong coupling of the
aromatic C-H(D) out-of-plane bending modes of polystyrene, deuterated
polystyrene, and poly (benzyl methacrylate) to the vacuum electromagnetic field
of the cavity enhance the electrical conductivity by at least six orders of
magnitude compared to the uncoupled polymers. The conductance is thermally
activated at the onset of strong coupling. It becomes temperature and cavity
path length independent at the highest coupling strengths, giving rise to the
extraordinary electrical conductance in these polymers. The electrical
characterizations are performed without external light excitation,
demonstrating the role of quantum light in enhancing the long-range coherent
transport even in amorphous non-conducting polymers.
