Háskóli ÍslandsUniversity of IcelandGrozdanov, SašoLucas, AndrewPoovuttikul, Napat2020-05-042020-05-042019-04-15Grozdanov, S., Lucas, A., & Poovuttikul, N. (2019). Holography and hydrodynamics with weakly broken symmetries. ArXiv.org, 99(8), ArXiv.org, Apr 16, 2019.2470-00102470-0029 (eISSN)https://hdl.handle.net/20.500.11815/1771Publisher's version (útgefin grein)Hydrodynamics is a theory of long-range excitations controlled by equations of motion that encode the conservation of a set of currents (energy, momentum, charge, etc.) associated with explicitly realized global symmetries. If a system possesses additional weakly broken symmetries, the low-energy hydrodynamic degrees of freedom also couple to a few other "approximately conserved" quantities with parametrically long relaxation times. It is often useful to consider such approximately conserved operators and corresponding new massive modes within the low-energy effective theory, which we refer to as quasihydrodynamics. Examples of quasihydrodynamics are numerous, with the most transparent among them hydrodynamics with weakly broken translational symmetry. Here, we show how a number of other theories, normally not thought of in this context, can also be understood within a broader framework of quasihydrodynamics: in particular, the Müller-Israel-Stewart theory and magnetohydrodynamics coupled to dynamical electric fields. While historical formulations of quasihydrodynamic theories were typically highly phenomenological, here, we develop a holographic formalism to systematically derive such theories from a (microscopic) dual gravitational description. Beyond laying out a general holographic algorithm, we show how the Müller-Israel-Stewart theory can be understood from a dual higher-derivative gravity theory and magnetohydrodynamics from a dual theory with two-form bulk fields. In the latter example, this allows us to unambiguously demonstrate the existence of dynamical photons in the holographic description of magnetohydrodynamics.086012eninfo:eu-repo/semantics/openAccessGauge-gravity dualitiesQuantum fluids & solidsStrongly correlated systemsSkammtafræðiÞéttefnisfræðiStraumfræðiinfo:eu-repo/semantics/articlePhysical Review D10.1103/PhysRevD.99.086012