Hall Viscosity and Angular Momentum in Gapless Holographic Models
نویسندگان
چکیده
We use the holographic approach to compare the Hall viscosity ηH and the angular momentum density J in gapless systems in 2 + 1 dimensions at finite temperature. We start with a conformal fixed point and turn on a perturbation which breaks the parity and time reversal symmetries via gauge and gravitational Chern-Simons couplings in the bulk. While the ratio of ηH and J shows some universal properties when the perturbation is slightly relevant, we find that the two quantities behave differently in general. In particular, ηH depends only on infrared physics, while J receives contributions from degrees of freedom at all scales.
منابع مشابه
On the Membrane Paradigm and Spontaneous Breaking of Horizon BMS Symmetries
Abstract We consider a BMS-type symmetry action on isolated horizons in asymptotically flat spacetimes. From the viewpoint of the non-relativistic field theory on a horizon membrane, supertranslations shift the field theory spatial momentum. The latter is related by a Ward identity to the particle number symmetry current and is spontaneously broken. The corresponding Goldstone boson shifts the ...
متن کاملOrbital analogue of the quantum anomalous Hall effect in p-band systems.
We investigate the topological insulating states of the p-band systems in optical lattices induced by the on site orbital angular momentum polarization, which exhibit gapless edge modes in the absence of Landau levels. This effect arises from the energy-level splitting between the on site p_{x}+ip_{y} and p_{x}-ip_{y} orbitals by rotating each optical lattice site around its own center. At larg...
متن کاملA Generic Theory of the Integer Quantum Hall Effect
The integer quantum Hall effect (IQHE) is usually modeled by a Galilean or rotationally invariant Hamiltonian. These are not generic symmetries for electrons moving in a crystal background and can potentially confuse non-topological quantities with topological ones and identify otherwise distinct geometrical properties. In this thesis we present a generic theory for the IQHE. First we show that...
متن کاملIntra-Landau-level magnetoexcitons and the transition between quantum Hall states in undoped bilayer graphene
We study the collective modes of the quantum Hall states in undoped bilayer graphene in a strong perpendicular magnetic and electric field. Both for the well-known ferromagnetic state that is relevant for small electric field E⊥ and the analogous layer polarized one suitable for large E⊥, the low-energy physics is dominated by magnetoexcitons with zero angular momentum that are even combination...
متن کاملThe Viscosity Bound Conjecture and Hydrodynamics of M2-brane Theory at Finite Chemical Potential
Kovtun, Son and Starinets have conjectured that the viscosity to entropy density ratio η/s is always bounded from below by a universal multiple of ~ i.e., ~/(4πkB) for all forms of matter. Mysteriously, the proposed viscosity bound appears to be saturated in all computations done whenever a supergravity dual is available. We consider the near horizon limit of a stack of M2-branes in the grand c...
متن کامل