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Causality Constraints in Conformal Field Theory

4 Pith papers cite this work. Polarity classification is still indexing.

4 Pith papers citing it
abstract

Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the $(\partial\phi)^4$ coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators.

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representative citing papers

Analyticity and positivity of Green's functions without Lorentz

hep-th · 2025-12-11 · unverdicted · novelty 7.0

Microcausality and positivity constrain Green's functions to be analytic in the forward light-cone with Im(ω G) > 0 in the complex domain for translation-invariant but Lorentz-breaking systems, implying integral constraints and analytic ε(ω,k), μ^{-1}(ω,k).

Response of interferometers to the vacuum of quantum gravity

hep-th · 2024-09-05 · unverdicted · novelty 5.0

Standard low-energy quantum gravity via effective graviton QFT predicts interferometer length variations of order the Planck length (~10^{-35} m), with no divergences indicating breakdown.

Boulder Lectures on Thermal Dynamics and Hydrodynamic EFTs

hep-th · 2026-06-01 · unverdicted · novelty 2.0

Lectures summarizing the construction of hydrodynamic EFTs through strong-to-weak symmetry breaking, with examples from spin chains to relativistic QFTs and UV/IR constraints on transport coefficients.

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Showing 4 of 4 citing papers.

  • The CFT Distance Conjecture and Tensionless String Limits in $\mathcal N=2$ Quiver Gauge Theories hep-th · 2026-01-13 · unverdicted · none · ref 70 · internal anchor

    In N=2 SU quiver theories the large-N Hagedorn temperature depends only on quiver length for linear cases and equals that of N=4 SYM for holographic quivers, with a universal lower bound of 1/sqrt(2) on the exponential rate alpha of higher-spin current conservation.

  • Analyticity and positivity of Green's functions without Lorentz hep-th · 2025-12-11 · unverdicted · none · ref 4 · internal anchor

    Microcausality and positivity constrain Green's functions to be analytic in the forward light-cone with Im(ω G) > 0 in the complex domain for translation-invariant but Lorentz-breaking systems, implying integral constraints and analytic ε(ω,k), μ^{-1}(ω,k).

  • Response of interferometers to the vacuum of quantum gravity hep-th · 2024-09-05 · unverdicted · none · ref 32 · internal anchor

    Standard low-energy quantum gravity via effective graviton QFT predicts interferometer length variations of order the Planck length (~10^{-35} m), with no divergences indicating breakdown.

  • Boulder Lectures on Thermal Dynamics and Hydrodynamic EFTs hep-th · 2026-06-01 · unverdicted · none · ref 25 · internal anchor

    Lectures summarizing the construction of hydrodynamic EFTs through strong-to-weak symmetry breaking, with examples from spin chains to relativistic QFTs and UV/IR constraints on transport coefficients.