5 papers
Kinetic backreaction cannot suppress axion quantum pressure
Kaleb Anderson, Savvas M. Koushiappas
Ultralight axions from string compactifications carry non-canonical kinetic terms whose normalization is set by a coupling function that depends on an accompanying modulus field. A…
Satellite-borne -ray astrophysics from coherent interactions in oriented crystals
Pietro Monti-Guarnieri, Gianfranco Paternò, Alexei Sytov +20
High-density and high-Z crystals are key elements of most space-borne -ray telescopes operating at gigaelectronvolt energies (such as Fermi-LAT). The lattice structure is usual…
A Cosmological Uncertainty Relation and Late-Universe Acceleration
Savvas M. Koushiappas
We propose that the size of the universe and its expansion rate cannot be simultaneously specified with arbitrary precision--a quantum mechanical uncertainty encoded via a deformed…
Kinetically Coupled Dark Matter Condensates
Michael W. Toomey, Savvas M. Koushiappas, Stephon Alexander
Dark matter consisting of ultralight bosons can form a macroscopic Bose-Einstein condensate with distinctive observational signatures. While this possibility has been extensively s…
Field Equations in Chern-Simons-Gauss-Bonnet Gravity
Alexis Ortega, Tatsuya Daniel, Savvas M. Koushiappas
We investigate the effects of Chern-Simons-Gauss-Bonnet gravity on fundamental metrics. This theory involves perturbative corrections to general relativity, as well as two scalar f…