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ASU Scholarship Showcase


This growing collection consists of scholarly works authored by ASU-affiliated faculty, students and community members, and contains many open access articles. ASU-affiliated authors are encouraged to Share Your Work in the ASU Digital Repository.


Axion stars are hypothetical objects formed of axions, obtained as localized and coherently oscillating solutions to their classical equation of motion. Depending on the value of the field amplitude at the core |θ[subscript 0]| ≡ |θ(r = 0)|, the equilibrium of the system arises from the balance of the kinetic pressure and either self-gravity or axion self-interactions. Starting from a general relativistic framework, we obtain the set of equations describing the configuration of the axion star, which we solve as a function of |θ[subscript 0]|. For small |θ[subscript 0]| [< over ~] 1, we reproduce results previously obtained in the …

Contributors
Visinelli, Luca, Baum, Sebastian, Redondo, Javier, et al.
Created Date
2017-12-06

The surprisingly large value of r, the ratio of power in tensor to scalar density perturbations in the CMB reported by the BICEP2 Collaboration, if confirmed, provides strong evidence for Inflation at the GUT scale. While the Inflationary signal remains the best motivated source, a large value of r alone would still allow for the possibility that a comparable gravitational wave background might result from a self ordering scalar field (SOSF) transition that takes place later at somewhat lower energy. We find that even without detailed considerations of the predicted BICEP signature of such a transition, simple existing limits on …

Contributors
Dent, James B., Krauss, Lawrence, Mathur, Harsh, et al.
Created Date
2014-07-30

Using a relation between the thermodynamics of local horizons and the null energy condition, we consider the effects of quantum corrections to the gravitational entropy. In particular, we find that the geometric form of the null energy condition is not affected by the inclusion of logarithmic corrections to the Bekenstein–Hawking entropy.

Contributors
Parikh, Maulik, Svesko, Andrew, College of Liberal Arts and Sciences, et al.
Created Date
2016-08-01

We show that effective theories of matter that classically violate the null energy condition cannot be minimally coupled to Einstein gravity without being inconsistent with both string theory and black hole thermodynamics. We argue however that they could still be either non-minimally coupled or coupled to higher-curvature theories of gravity.

Contributors
Chatterjee, Saugata, Parikh, Maulik, van der Schaar, Jan Pieter, et al.
Created Date
2015-03-16

We study the exclusive double-photon annihilation processes, e[superscript +]e[superscript −] → γγ[superscript ⁎] → γV[superscript 0] and e[superscript +]e[superscript −] → γ[superscript ⁎]γ[superscript ⁎] → V[0 over a]V[0 over b], where the V[0 over i] is a neutral vector meson produced in the forward kinematical region: s >> −t and −t >> A[2 over QCD]. We show how the differential cross sections [dσ over dt], as predicted by QCD, have additional falloff in the momentum transfer squared t due to the QCD compositeness of the hadrons, consistent with the leading-twist fixed-θ[subscript CM] scaling laws, both in terms of conventional Feynman …

Contributors
Brodsky, Stanley J., Lebed, Richard, Lyubovitskij, Valery E., et al.
Created Date
2016-11-17

Starting with the dynamical picture of the exotic c[¯over c]-containing states XYZas the confinement-induced hadronization of a rapidly separating pair of a compact diquark and antidiquark, we describe the pentaquark candidates P[+ over c](4380)and P[+ over c](4450)in terms of a confined but rapidly separating color-antitriplet diquark cuand color-triplet “triquark” [¯ over c](ud). This separation explains the relatively small P[+ over c] widths, despite these 5-quark systems lying far above both the J/ψp and A[subscript c] [¯ over D][superscript (∗)0] thresholds. The P[+ over c] states are predicted to form isospin doublets with neutral partners P[0 over c].

Contributors
Lebed, Richard, College of Liberal Arts and Sciences, Department of Physics
Created Date
2015-08-17