Peripheral collisions of heavy ions can give rise to extremely intensemagnetic fields. It has been suggested that these fields might invalidate theholographic description of the corresponding quark-gluon plasmas, assuming thatthese can be modelled by strongly coupled field theories. In the case of theplasmas produced in collisions at the RHIC facility (including in the beamenergy scans), it is known how to deal with this problem: one has to take intoaccount the large angular momenta generated in these plasmas, and the effectsof the baryonic chemical potential. But this does not work for the plasmasproduced in peripheral collisions at the LHC. However, these results neglectsome (less significant) aspects of bulk physics; could it be that the problemis resolved by taking into account these lower-order effects? Here we use abulk dilatonic field (fully compatible with boundary data, as well as with theasymptotically AdS character of the bulk geometry) as a model of these effects,and show that this is unlikely to be the solution. Thus, the existence of aconsistent holographic description of the most extreme LHC plasmas remains opento question.
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