A note on the holographic interpretation of string theory backgrounds with varying flux

We discuss the field theory interpretation (via holographic duality) of some recently-discovered string theory solutions with varying flux, focusing on four-dimensional theories with N = 2 supersymmetry and with N = 1 supersymmetry which arise as the near-horizon limits of fractional D3-branes. We argue that in the N = 2 case the best interpretation of the varying flux in field theory is via a Higgs mechanism reducing the rank of the gauge group, and that there is no need to invoke a duality to explain the varying flux in this case. We discuss why a similar interpretation does not seem to apply to the N = 1 case of Klebanov and Strassler, which was interpreted as a duality cascade. However, we suggest that it might apply to different vacua of the same theory, such as the one constructed by Pando Zayas and Tseytlin.