Related papers: Paper-boat relaxion
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 canonical front form Hamiltonian for non-Abelian SU(N) gauge theory in 3+1 dimensions and in the light-cone gauge is mapped non-perturbatively on an effective Hamiltonian which acts only in the Fock space of a quark and an antiquark.…
The first paper in this series showed that QCD axion dark matter, as a highly-correlated Bose fluid, contains extra-classical physics on cosmological scales. The nature of the derived extra-classical physics is exchange-correlation…
The Higgs mechanism is the favourite cure for the main problem with electroweak unification, namely how to reconcile a gauge theory with the need for massive gauge bosons. This problem does not exist in preon models for quark and lepton…
Slightly extending a right-handed neutrino version of the $3-3-1$ model, we show that it is not only possible to solve the strong CP problem but also to give the total dark matter abundance reported by the Planck collaboration.…
The recent measurement of a cutoff k_min in the fluctuation power spectrum P(k) of the cosmic microwave background may vitiate the possibility that slow-roll inflation can simultaneously solve the horizon problem and account for the…
We present a novel framework for obtaining large hierarchies in axion decay constants as well as trans-Planckian field excursions, with no need for tuning or a large number of fields. We consider a model with two or more CFTs with a common…
We revisit scale separation for compactifications of ten- and eleven-dimensional supergravity. For cosmological solutions rolling down flux-generated potentials, we observe that scale separation is achieved as time flows, and is fairly…
The Lorentzian Hamiltonian constraint is solved for isotropic loop quantum cosmology coupled to a massless scalar field. As in the Euclidean case, the discreteness of quantum geometry removes the classical singularity from the quantum…
We present a scale invariant extension of the Standard model allowing for the Kim-Shifman-Vainstein-Zakharov (KSVZ) axion solution of the strong CP problem in QCD. We add the minimal number of new particles and show that the Peccei-Quinn…
We consider QCD axion models where the Peccei-Quinn symmetry is badly broken by a larger amount in the past than in the present, in order to avoid the axion isocurvature problem. Specifically we study supersymmetric axion models where the…
We present a scenario where an axion-like field drives inflation until a potential barrier, which keeps a waterfall field at the origin, disappears and a waterfall transition occurs. Such a barrier separates the scale of inflation from that…
We propose a minimal realization of the Peccei Quinn mechanism in a realistic SU(5) model, where the axion mass is directly connected to the grand-unification scale. By taking into account constraints from proton decay, collider searches…
We attempt to identify a phenomenologically viable solution to the strong $CP$ problem in which the axion is composed entirely out of Standard Model fermion species. The axion consists predominantly of the $\eta'$ meson with a minuscule…
Complex scalar fields charged under approximate $U(1)$ symmetries appear in well-motivated extensions of the Standard Model. One example is the field that contains the QCD axion field associated with the Peccei-Quinn symmetry; others…
We have recently proposed a model for a regular black hole, or an ultra-compact object, that is premised on having maximally negative radial pressure throughout the entirety of the object's interior. This model can be viewed as that of a…
Dark matter may be composed of light bosons, ${m_b \sim 10^{-22}\, \mathrm{eV}}$, with a de Broglie wavelength $\lambda \sim 1 \,\mathrm{kpc}$ in typical galactic potentials. Such `fuzzy' dark matter (FDM) behaves like cold dark matter…
The mechanism of "cold electroweak baryogenesis" has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We…
The QCD axion is one of the most appealing candidates for the dark matter in the Universe. In this article, we discuss the possibility to predict the axion mass in the context of a simple renormalizable grand unified theory where the…
The issue of a self-consistent solution of Maxwell-Einstein equations achieves a very simple form when all quantum effects are neglected but a weak vacuum polarization due to an external magnetic field is taken into account. From a…