Signatures of short distance physics in the cosmic microwave background

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

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We systematically investigate the effect of short distance physics on the spectrum of temperature anistropies in the Cosmic Microwave Background produced during inflation. We present a general argument-assuming only low energy locality-that the size of such effects are of order H^2/M^2, where H is the Hubble parameter during inflation, and M is the scale of the high energy physics. We evaluate the strength of such effects in a number of specific string and M theory models. In weakly coupled field theory and string theory models, the effects are far too small to be observed. In phenomenologically attractive Horava-Witten compactifications, the effects are much larger but still unobservable. In certain M theory models, for which the fundamental Planck scale is several orders of magnitude below the conventional scale of grand unification, the effects may be on the threshold of detectability. However, observations of both the scalar and tensor fluctuation contributions to the Cosmic Microwave Background power spectrum-with a precision near the cosmic variance limit-are necessary in order to unambiguously demonstrate the existence of these signatures of high energy physics. This is a formidable experimental challenge.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c509e79a2639778a63f5ec4a9b92974d66338672

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Citations in the corpus

Modern Tests of Lorentz Invariance (2005, background): “A number of authors have addressed the possible signatures of trans-Planckian physics in the CMB, for a sampling see [94, 212, 214, 262, 101, 164, 66, 236] and references therein.”
Noncommutative spacetime, stringy spacetime uncertainty principle, and density fluctuations (2002, background): “The uncertainty relation has no significant effect for these modes, in agreement with the general consideration of [22].”
Are inflationary predictions sensitive to very high energy physics (2002, background): “2.1 Conditions for Inflation 4 2.2 χ Oscillations and a Possible Pre-Inflationary Phase 5”
The Holographic principle (2002, background): “18Low (2002) has argued that the future directed light sheets in cosmological spacetimes can be made arbitrarily extensive by choosing a closed surface containing sufficiently flat pieces.”
An ignoble approach to large field inflation (2010, methodology): “In string and M-theory models consistent with grand unification, the fundamental string and/or 10/11dimensional Planck scales are close to the GUT scale, often within a factor of 10 or so (see for example [58], and references therein, for a discussion.”
Analogue Gravity (2005, background): “We expect that these analogue models provide us with new insights as to how their inherent modified dispersion relations affect cosmological process such as the generation of a primordial spectrum of perturbations (see for example [250, 251, 46, 42, 41, 107, 209, 229, 230, 249, 275, 275, 274, 43, 47”
Initial Conditions for Inflation (2002, background): “The effect is of order H/M , where M is the scale of new physics, which is larger than the H(2)/M(2) effects discussed in [6,3].”
On graviton non-gaussianities during inflation (2011, background): “[33] Nemanja Kaloper, Matthew Kleban, Albion E.”
Trans-Planckian issues for inflationary cosmology (2012, unknown): “Specifically, one can consider the example [25, 26]”
Monodromy in the CMB: Gravity Waves and String Inflation (2008, background): “lly testable inﬂation looks from a model-building point of view. Indeed, without considering speciﬁc mechanisms, the problem of testing UV-sensitive contributions to inﬂation is very diﬃcult a priori [37]. The present construction involves modest ﬁne-tuning and a simple mechanism for enhancing the g”
Oscillations in the CMB from axion monodromy inflation (2009, unknown): “39) also shows that instead of starting in the Bunch-Davies state and then following the mode through the resonance, one may start the evolution after the resonance has occurred but use a state that is different from the Bunch-Davies state, which is similar to what is considered in [22, 23, 8, 9, 10”