Resilience of long modes in cosmological observables

Abstract

By a careful implementation of gauge transformations involving long-wavelength modes, we show that a variety of effects involving squeezed bispectrum configurations, for which one Fourier mode is much shorter than the other two, cannot be gauged away, except for the unphysical exactly infinite-wavelength ($k=0$) limit. Our result applies, in particular, to the Maldacena consistency relation for single-field inflation, yielding a local non-Gaussianity strength $f_{\mathrm{NL}}^{\mathrm{local}}=-(5/12)(n_S-1)$ (with $n_S$ the primordial spectral index of scalar perturbations), and to the $f_{\mathrm{NL}}^{\mathrm{GR}}=-5/3$ term, appearing in the dark matter bispectrum and in the halo bias, as a consequence of the general relativistic non-linear evolution of matter perturbations. Such effects are therefore physical and observable in principle by future high-sensitivity experiments.

19 pages, no figures. LaTex. Version accepted for publication in JCAP, minor changes

References in corpus (7)

• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• On the consistency relation of the 3-point function in single field inflation
• Conformal Symmetries of Adiabatic Modes in Cosmology
• Non-gaussianity from the second-order cosmological perturbation
• Sachs-Wolfe at second order: the CMB bispectrum on large angular scales
• General relativistic corrections and non-Gaussianity in large scale structure
• How Gaussian can the Sky be? Primordial Non-Gaussianity from Quantum Information

Cited by in corpus (22)

• PBHs and secondary GWs from ultra slow roll and punctuated inflation
• Probing non-Gaussianities with the high frequency tail of induced gravitational waves
• Tensor non-Gaussianity in chiral scalar-tensor theories of gravity
• Quijote-PNG: Simulations of primordial non-Gaussianity and the information content of the matter field power spectrum and bispectrum
• Solving peak theory in the presence of local non-gaussianities
• Universal signature of quantum entanglement across cosmological distances
• Local primordial non-Gaussianity in the relativistic galaxy bispectrum
• Large Scale Limit of the Observed Galaxy Power Spectrum
• CMB $\mu T$ cross-correlations as a probe of PBH scenarios
• Smooth vs instant inflationary transitions: steepest growth re-examined and primordial black holes
• Primordial Stochastic Gravitational Wave Background Anisotropies: in-in Formalization and Applications
• Anisotropic separate universe and Weinberg's adiabatic mode
• The limits of cosmology: role of the Moon
• Primordial Non-Gaussianity in Supersolid Inflation
• Unifying attractor and non-attractor models of inflation under a single soft theorem
• The Physical Content of Long Tensor Modes in Cosmology
• Large gauge transformations, local coordinates and cosmological observables
• Including relativistic and primordial Non-Gaussianity contributions in cosmological simulations by modifying the initial condition
• Incompatibility of Standard Galaxy Bias Models in General Relativity
• Breaking the Single Clock Symmetry: measuring single-field inflation non-Gaussian features
• Quijote PNG: The information content of the halo power spectrum and bispectrum
• Non-Gaussianity in the Squeezed Three-Point Correlation from the Relativistic Effects