Abstract
We consider a neutral holographic plasma with dynamical electromagnetic interactions in a finite external magnetic field. The Coulomb interactions are introduced via mixed boundary conditions for the Maxwell gauge field. The collective modes at finite wave-vector are analyzed in detail and compared to the magneto-hydrodynamics results valid only at small magnetic fields. Surprisingly, at large magnetic field, we observe the appearance of two plasmon-like modes whose corresponding effective plasma frequency grows with the magnetic field and is not supported by any background charge density. Finally, we identify a mode collision which allows us to study the radius of convergence of the linearized hydrodynamics expansion as a function of the external magnetic field. We find that the radius of convergence in momentum space, related to the diffusive transverse electromagnetic mode, increases quadratically with the strength of the magnetic field.
Highlights
JHEP06(2021)014 electrons, a phenomenon driven by the polarization in the medium
In this paper we will extend our previous studies of collective modes in polarizable holographic media [22, 23] to incorporate a non-zero magnetic field, since this is an important experimental scenario
We will start by making a detailed comparison of our results to the state-of-the-art treatment of relativistic magnetohydrodynamics [11, 24,25,26,27,28,29,30,31,32,33,34,35,36], i.e. hydrodynamics coupled to dynamical electromagnetic fields [24]
Summary
We consider a simple Einstein-Maxwell action in four bulk dimensions defined by the action. Which are equivalent to the familiar conditions of the dielectric function, e.g (ω, k) = 0 for longitudinal excitations [37], and allow for dynamical electromagnetic interactions in the dual field theory without a driving external current, as needed for obtaining collective modes. This is a crucial difference with respect to the previous studies considering the same Reissner-Nordström dyonic black hole solution [38, 39].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
