Spectral sum rules for conformal field theories in arbitrary dimensions

Abstract

We derive spectral sum rules in the shear channel for conformal field theories at finite temperature in general $d\ge 3$ dimensions. The sum rules result from the OPE of the stress tensor at high frequency as well as the hydrodynamic behaviour of the theory at low frequencies. The sum rule states that a weighted integral of the spectral density over frequencies is proportional to the energy density of the theory. We show that the proportionality constant can be written in terms the Hofman-Maldacena variables $t_2,t_4$ which determine the three point function of the stress tensor. For theories which admit a two derivative gravity dual this proportionality constant is given by $\frac{d}{2(d+1)}$. We then use causality constraints and obtain bounds on the sum rule which are valid in any conformal field theory. Finally we demonstrate that the high frequency behaviour of the spectral function in the vector and the tensor channel are also determined by the Hofman-Maldacena variables.

Corrected typos, JHEP version

References in corpus (12)

• N=6 superconformal Chern-Simons-matter theories, M2-branes and their gravity duals
• Minkowski-space correlators in AdS/CFT correspondence: recipe and applications
• Conformal collider physics: Energy and charge correlations
• A calculation of the bulk viscosity in SU(3) gluodynamics
• Spectral functions at small energies and the electrical conductivity in hot, quenched lattice QCD
• Bulk viscosity of QCD matter near the critical temperature
• Conformal Nonlinear Fluid Dynamics from Gravity in Arbitrary Dimensions
• Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography
• The quasi-normal modes of quantum criticality
• Energy Flux Positivity and Unitarity in CFTs
• Sum Rules from an Extra Dimension
• Constraining quantum critical dynamics: 2+1D Ising model and beyond

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