The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
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Enhanced Non-Gaussianity from Excited Initial States
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We use the techniques of effective field theory in an expanding universe to examine the effect of choosing an excited inflationary initial state built over the Bunch-Davies state on the CMB bi-spectrum. We find that even for Hadamard states, there are unexpected enhancements in the bi-spectrum for certain configurations in momentum space due to interactions of modes in the early stages of inflation. These enhancements can be parametrically larger than the standard ones and are potentially observable in current and future data. These initial state effects have a characteristic signature in $l$-space which distinguishes them from the usual contributions, with the enhancement being most pronounced for configurations corresponding to flattened triangles for which two momenta are collinear.
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Non-Bunch-Davies initial conditions substantially improve the fit of various single-field slow-roll inflation models to updated n_s-r constraints from ACT DR6 combined with Planck, DESI, and BICEP/Keck data.
Classical and quantum correlation functions of inflationary perturbations diverge exponentially with e-folds when interactions are relevant, even if forced to agree at an intermediate time.
Long inflation screens Euclidean wormhole initial states from the CMB, turning them into Bunch-Davies predictions and providing a bound on inflationary duration via visibility limits on Bogoliubov excitations.
DESI will target luminous red galaxies to z=1, emission-line galaxies to z=1.7, quasars for tracers and Ly-alpha forest at 2.1<z<3.5, plus a bright galaxy survey, to obtain more than 30 million redshifts for BAO and matter power spectrum measurements.
citing papers explorer
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Massive Exchange and the Sign of the Equilateral Bispectrum
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
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ACT-ing on inflation: Implications of non Bunch-Davies initial condition and reheating on single-field slow roll models
Non-Bunch-Davies initial conditions substantially improve the fit of various single-field slow-roll inflation models to updated n_s-r constraints from ACT DR6 combined with Planck, DESI, and BICEP/Keck data.
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Classical and quantum evolution of inflationary fluctuations
Classical and quantum correlation functions of inflationary perturbations diverge exponentially with e-folds when interactions are relevant, even if forced to agree at an intermediate time.
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Long Inflation Screens Euclidean-Wormhole Initial States
Long inflation screens Euclidean wormhole initial states from the CMB, turning them into Bunch-Davies predictions and providing a bound on inflationary duration via visibility limits on Bogoliubov excitations.
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The DESI Experiment Part I: Science,Targeting, and Survey Design
DESI will target luminous red galaxies to z=1, emission-line galaxies to z=1.7, quasars for tracers and Ly-alpha forest at 2.1<z<3.5, plus a bright galaxy survey, to obtain more than 30 million redshifts for BAO and matter power spectrum measurements.