Worldline holographic Schwinger effect
  The decay of the vacuum due to the presence of an electric field is expected to be delayed by a confining force. We demonstrate that this feature is captured by our model [arXiv:1404.0011 [hep-ph],arXiv:1312.5718 [hep-ph]] for hadrons based on the worldline formalism. Our model, while based entirely in four-dimensional quantum field theory, shares many features with holographic approaches: it appears intrinsically quantum mechanical; as an auxiliary fifth dimension Schwinger's proper time combines with the physical four spacetime dimensions into an AdS$_5$ geometry; conformal-symmetry breaking contributions lead to warping; hidden local symmetry emerges; four-dimensional sources are extended to five-dimensional fields by a Wilson flow (gradient flow); and a variational principle for this flow reproduces the corresponding holographic calculation. The approach also yields the higher-dimensional description in the non-relativistic case. 
Dennis D. Dietrich
hep-ph hep-th nucl-th