Monodromy in the CMB: Gravity Waves and String Inflation

By E. Silverstein, A. Westphal. 2008

935 citations recorded by the source corpus.

We present a simple mechanism for obtaining large-field inflation, and hence a gravitational wave signature, from string theory compactified on twisted tori. For nil manifolds, we obtain a leading inflationary potential proportional to {phi}{sup 2/3} in terms of the canonically normalized field {phi}, yielding predictions for the tilt of the power spectrum and the tensor-to-scalar ratio, n{sub s}{approx_equal}0.98 and r{approx_equal}0.04 with 60 e-foldings of inflation; we note also the possibility of a variant with a candidate inflaton potential proportional to {phi}{sup 2/5}. The basic mechanism involved in extending the field range--monodromy in D-branes as they move in circles on the manifold--arises in a more general class of compactifications, though our methods for controlling the corrections to the slow-roll parameters require additional symmetries.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/bb64aaadf61fb7aa1950a5c056999ee2ee19adc9

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Citations in the corpus

Resonant non-gaussianity (2010, positive): “Most of the numerical calculations were done for the linear potential relevant for axion monodromy inflation, but we have also performed some checks for the case of a quadratic potential as well as V0(φ) = μ φ motivated by [21].”
The powers of monodromy (2014, background): “Our discussion here is not exhaustive: other examples include configurations with moving branes [24, 32, 33, 35], as well as some of the scenarios in [36–47]; some of these may also be understood via dualities.”
Axion cosmology and the energy scale of inflation (2008, background): “For such models, Ne around 50 or 60 is expected, so any reasonable p is ruled out, including φ2 chaotic inflation [4] and the stringy Nflation [37] and Monodromy [38] models.”
The Swampland: Introduction and Review (2019, background): “However, they became particularly studied once it was realized that they are very interesting candidates for inflatons in large field inflation [310].”
Using the Full Power of the Cosmic Microwave Background to Probe Axion Dark Matter (2017, background): “The ULA mass, ma, is effectively time-independent for geometric (closed string) axions in string theory (Svrcek & Witten 2006), and the self-interaction potential for string axions can take a wide variety of functional forms (e.g. Silverstein & Westphal 2008; Jaeckel et al. 2017).”
Towards universal axion inflation and reheating in string theory (2014, background): “A second variation is so-called axion monodromy inflation [10–12], where the shift symmetry is broken by the presence of a brane, inducing an approximately linear (or quadratic) potential for the axion.”
Trapped Inflation (2009, background): “To begin, consider wrapped D4-branes in type IIA string compactifications on nilmanifolds, as in [14, 30].”
Gauge-preheating and the end of axion inflation (2015, background): “More recently, the observation that a single axion undergoing monodromy can have a small periodicity while ultimately traversing a large field range [15, 16] has seen resurgent interest in axion inflation [17–22].”
On the cosmological implications of the string Swampland (2018, methodology): “Axion monodromy models [14], N-flation [24] and other multifield models were introduced to ensure”
Particle production during inflation and gravitational waves detectable by ground-based interferometers (2011, background): “Other forms of the potential for a pseudoscalar inﬂaton were considered in the models of inﬂation from axion monodromy [32–34], and we expect that the predictions from these models will not diﬀer signiﬁcantly from those presented here.”
Two-field high-scale inflation in a sub-Planckian region of field space (2009, methodology): “The construction is a simple generalization of the axion monodromy models constructed in [7, 8, 9].”
Planckian axions and the Weak Gravity Conjecture (2015, background): “In axion monodromy scenarios [5, 6], multiple traversals of a sub-Planckian fundamental period lead to a super-Planckian displacement.”