Natural inflation with multiple sub-Planckian axions

By Kiwoon Choi, Hyungjin Kim, Seokhoon Yun. 2014

220 citations recorded by the source corpus.

We extend the Kim-Nilles-Peloso (KNP) alignment mechanism for natural inflation to models with N > 2 axions, which obtains super-Planckian effective axion decay constant f eff ≫ M Pl through an alignment of the anomaly coefficients of multiple axions having sub-Planckian fundamental decay constants f 0 ≪ M Pl . The original version of the KNP mechanism realized with two axions requires that some of the anomaly coefficients should be of the order of f eff / f 0 , which would be uncomfortably large if f eff / f 0 ≳ O ( 100 ) as suggested by the recent BICEP2 results. We note that the KNP mechanism can be realized with the anomaly coefficients of O ( 1 ) if the number of axions N is large as N ln N ≳ 2 ln ( f eff / f 0 ) , in which case the effective decay constant can be enhanced as f eff / f 0 ∼ N ! n N − 1 for n denoting the typical size of the integer-valued anomaly coefficients. Comparing to the other multiple axion scenario, the N -flation scenario which requires N ∼ f eff 2 / f 0 2 , the KNP mechanism has a virtue of not invoking to a too large number of axions, although it requires a specific alignment of the anomaly coefficients, which can be achieved with a probability of O ( f 0 / f eff ) under a random choice of the anomaly coefficients. We also present a simple model realizing a multiple axion monodromy along the inflaton direction.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/763f92a2ee3e89934457a1fcdcca29561a381cf1

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Eran Palti
2. Kiwoon Choi
3. Pablo Soler
4. Sang Hui Im
5. C. Shin
6. William Cottrell
7. A. Hook
8. Jon Brown

In Nuclear and High Energy Physics

1. Eran Palti
2. Pablo Soler
3. Kiwoon Choi
4. Sang Hui Im
5. C. Shin
6. Gary Shiu
7. William Cottrell
8. A. Hook

Citations in the corpus

• Recent Progress in the Physics of Axions and Axion-Like Particles (2020, background): “In fact, |n̂a| 1 is a generic feature of the axion landscape scenario with NH NL [117, 118].”
• Constraints on axion inflation from the weak gravity conjecture (2015, unknown): “[5–19]).”
• The landscape of QCD axion models (2020, unknown): “‘clockwork’ type of constructions [537–540].”
• Dark photon dark matter produced by axion oscillations (2018, unknown): “[41] K.”
• Fencing in the swampland: quantum gravity constraints on large field inflation (2015, background): “Most efforts in constructing large field inflation models have therefore been focused on evading this constraint by a variety of EFT mechanisms involving multiple axions [5–7].”
• Winding out of the Swamp: Evading the Weak Gravity Conjecture with F-term Winding Inflation? (2015, background): “Recently, a wealth of models based on all these approaches appeared in the literature [9–36].”
• TASI Lectures on the Strong CP Problem and Axions (2018, background): “Although these approaches have been around for a long time [64, 65], a move of marketing genius has recently renamed them as clockwork models [66, 67].”