Initial Conditions for Inflation

By N. Kaloper, Matthew Kleban, A. Lawrence, S. Shenker, L. Susskind. 2002

270 citations recorded by the source corpus.

Free scalar fields in de Sitter space have a one-parameter family of states invariant under the de Sitter group, including the standard thermal vacuum. We show that, except for the thermal vacuum, these states are unphysical when gravitational interactions are included. We apply these observations to the quantum state of the inflaton, and find that at best, dramatic fine tuning is required for states other than the thermal vacuum to lead to observable features in the CMBR anisotropy.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/e3324efd02d7dda57d8adb6df73711465c061951

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Citations in the corpus

Spontaneous inflation and the origin of the arrow of time (2004, background): “) In order for inflation to begin, there must be a region that is smooth, dominated by potential energy, and of radius LI larger than H −1 I [46, 47, 48, 49].”
An ignoble approach to large field inflation (2010, background): “If the inflaton began in a state excited above the Bunch-Davies vacuum, while the excitation will inflate away after a few efoldings [74], it could lead to additional observable effects [75].”
Inflationary Cosmology after Planck 2013 (2014, methodology): “In [172] the authors used my own approach proposed in [21] and described in section 4 of these lectures, where I argued that the simplest versions of inflationary cosmology, the ones where inflation can start at the Planck density, do not suffer from the problem of initial conditions.”
Trans-Planckian issues for inflationary cosmology (2012, background): “The use of such vacua has, however, been criticized on the basis of their instabilities [36, 37] (but see [38]).”
Inflation and de Sitter thermodynamics (2002, background): “Thermal vacuum in the causal patch (“hot tin can”) corresponds to the BunchDavies vacuum of the metric (1) [14,15] and gives a complementary picture of scalar field(s) fluctuations.”
Quantum Gravity in Everyday Life: General Relativity as an Effective Field Theory (2003, background): “In this case most kinds of heavy physics decouple, and the vast majority of effects it can produce for the microwave background can be argued to be smaller than O(H/M) [99, 98].”
Observational consequences of a landscape (2005, background): “teq ∼ H −1 logmp/H, (5.4) where mp is the Planck mass [ 24 ].”