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We consider a probe U(1) Maxwell-Chern-Simons theory in 5-dimensions, and analyze the vector perturbations around a classical charged black-brane background. We solve the equations of motion for these perturbations in a derivative expansion. By computing the boundary current, we find that time and spatial derivatives can be interpreted as the induced electric and magnetic field respectively, and the Chern-Simons term contributes to a nonzero divergence of the boundary current which indicates a quantum anomaly. Using holography, we construct a two-derivative effective action for the vector perturbations. By complexifying the radial coordinate, and using appropriate transformation, we construct the full solution on the complexified bulk contour. By computing the on-shell action for the full Schwinger-Keldysh geometry, we obtain the Keldysh functional. We find that the single boundary on-shell action mixes parity, whereas the Keldysh functional does not depend on the Chern-Simons term up to the quadratic orders in derivative expansion.

Abstract Lorentz symmetry forbids decays of massive spin-1 particle like the Z 0 into two massless photons, a result known as the Landau-Yang theorem. But it is known that infrared effects can break Lorentz invariance. Employing the construction of Mund et al. [1] which incorporated this Lorentz violation, we propose an interaction leading to the decay Z 0 → 2γ and study the dependence of the decay on the parameter of this Lorentz violation.

Abstract In contrast to the Einstein-Hilbert action, the action for self-dual gravity contains vierbeins. They are eleminated at the level of observables by an SL(2, ℂ) gauge condition implied by the action. We argue that despite this condition, new “edge” or superselected state vectors corresponding to maps of the spheres S ∞2 at infinity to SL(2, ℂ) arise. They are characterised by new quantum numbers and they lead to mixed states. For black holes, they arise both at the horizon and the spatial infinity and may be relevant for the black hole information paradox. Similar comments can be made about the EinsteinPalatini action which uses vierbeins.