Related papers: QCD Axion Hybrid Inflation
We show that the initial misalignment angle of the QCD axion (or axion-like particles) can be set very close to $\pi$, if the QCD axion has a mixing with another heavy axion which induces the phase shift $\approx \pi$ after inflation. In…
We propose the first model of warm inflation in which the particle production emerges directly from coupling the inflaton to Standard Model particles. Warm inflation, an early epoch of sustained accelerated expansion at finite temperature,…
We examine the theoretical possibility for the heavy QCD axion to induce slow-roll inflation while solving the strong CP problem through the Peccei-Quinn mechanism. If the cancellation between contributions from a small-size instanton and…
A direct coupling between the inflaton and Standard Model gluons can dynamically raise the QCD confinement scale during inflation, making the axion temporarily heavy and suppressing axion isocurvature perturbations. As inflation proceeds,…
The QCD axion solves the strong CP problem and represents an attractive particle candidate for cold dark matter (CDM). However, quantum fluctuations of the axion field during inflation easily result in large CDM isocurvature perturbations…
A model of high scale inflation is presented where the radial part of the Peccei-Quinn (PQ) field with a non-minimal coupling to gravity plays the role of the inflaton, and the QCD axion is the dark matter. A quantum fluctuation of…
We investigate the reheating process in an axion inflation model where the inflaton couples to non-Abelian gauge fields via the Chern-Simons coupling. The Chern-Simons coupling leads to the efficient production of gauge fields via a…
We show how successful supersymmetric hybrid inflation is realized in realistic models where the resolution of the minimal supersymmetric standard model mu problem is intimately linked with axion physics. The scalar fields that accompany…
Many models of dark matter QCD axion requires inflation at a scale $H_{\text{inf}} \lesssim 10^{6}$~GeV and hence does not allow for a detectable tensor mode fluctuation. This is because the domain wall problem forces the Peccei--Quinn…
A kinetic mixing between the axion and the inflaton allows for a production of axion dark matter even if the inflationary Hubble scale is smaller than the zero-temperature axion mass. We analyze the axion dynamics in this recently…
We show that the QCD axion can drive inflation via a series of tunneling events. For axion models with a softly broken $Z_N$ symmetry, the axion potential has a series of $N$ local minima and may be modeled by a tilted cosine. Chain…
We consider a model of inflation in which the inflaton field is a rolling axion with a potential which is flat enough to support an intermediate phase of USR inflation. Because of the Chern-Simons interaction, one polarization of the gauge…
Slow-roll inflation is a successful paradigm. However we find that even a small coupling of the inflaton to other light fields can dramatically alter the dynamics and predictions of inflation. As an example, the inflaton can generically…
We show that the hybrid inflation is naturally realized in the framework of a supersymmetric axion model, which is consistent with the WMAP observation if the Peccei-Quinn symmetry breaking scale is around 10^{15}GeV. By solving the post…
String and M-theory compactifications generically have compact moduli which can potentially act as the QCD axion. However, as demonstrated here, such a compact modulus can not play the role of a QCD axion and solve the strong CP problem if…
The QCD axion is one of the best motivated dark matter candidates. The misalignment mechanism is well known to produce an abundance of the QCD axion consistent with dark matter for an axion decay constant of order $10^{12}$ GeV. For a…
In order to accommodate the QCD axion as the dark matter (DM) in a model in which the Peccei-Quinn (PQ) symmetry is broken before the end of inflation, a relatively low scale of inflation has to be invoked in order to avoid bounds from DM…
We show that the upper bound of the classical QCD axion window can be significantly relaxed for low-scale inflation. If the Gibbons-Hawking temperature during inflation is lower than the QCD scale, the initial QCD axion misalignment angle…
The QCD axion is the leading solution to the strong-CP problem, a dark matter candidate, and a possible result of string theory compactifications. However, for axions produced before inflation, symmetry-breaking scales of $f_a \gtrsim…
We propose a new mechanism to produce axion dark matter from inflationary fluctuations. Quantum fluctuations during inflation are strengthened by a coupling of the axion kinetic term to the inflaton, which we parametrize as an effective…