An infinite set of Ward identities for adiabatic modes in cosmology

Journal Article · Wed Jan 01 04:00:00 EST 2014 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2014/01/039· OSTI ID:22369795

Hinterbichler, Kurt ^[1]; Hui, Lam ^[2]; Khoury, Justin ^[3]

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1. Perimeter Institute for Theoretical Physics, 31 Caroline St. N, Waterloo, Ontario, N2L 2Y5 (Canada)
2. Physics Department and Institute for Strings, Cosmology and Astroparticle Physics, Columbia University, 538 W 120 St., New York, NY 10027 (United States)
3. Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)

We show that the correlation functions of any single-field cosmological model with constant growing-modes are constrained by an infinite number of novel consistency relations, which relate N+1-point correlation functions with a soft-momentum scalar or tensor mode to a symmetry transformation on N-point correlation functions of hard-momentum modes. We derive these consistency relations from Ward identities for an infinite tower of non-linearly realized global symmetries governing scalar and tensor perturbations. These symmetries can be labeled by an integer n. At each order n, the consistency relations constrain — completely for n = 0,1, and partially for n ≥ 2 — the q{sup n} behavior of the soft limits. The identities at n = 0 recover Maldacena's original consistency relations for a soft scalar and tensor mode, n = 1 gives the recently-discovered conformal consistency relations, and the identities for n ≥ 2 are new. As a check, we verify directly that the n = 2 identity is satisfied by known correlation functions in slow-roll inflation.

• OSTI ID: 22369795
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 01 Vol. 2014; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CORRELATION FUNCTIONS
COSMOLOGICAL INFLATION
COSMOLOGICAL MODELS
COSMOLOGY
NONLINEAR PROBLEMS
POWER TRANSMISSION TOWERS
SCALARS
SYMMETRY
TENSORS
WARD IDENTITY