Entropy, Contact Interaction with Horizon and Dark Energy
  We present some arguments suggesting that the mismatch between Bekenstein-
Hawking entropy and the entropy of entanglement for vector fields is due to the
same gauge configurations which saturate the contact term in topological
susceptibility in QCD. In both cases the extra term with a "wrong sign" is due
to distinct topological sectors in gauge theories. This extra term has
non-dispersive nature, can not be restored from conventional spectral function
through dispersion relations, and can not be associated with any physical
propagating degrees of freedom. We make few comments on some profound
consequences of our findings. In particular, we speculate that the source of
the observed dark energy may also be related to the same type of gauge
configurations which are responsible for the mismatch between black hole
entropy and the entropy of entanglement in the presence of causal horizon.
