Ali Övgün

Chromatic Weak Lensing of a Generic Spherical Spacetime Through Millicharged Dark Matter Media

We study photon scattering in a transparent dispersive medium around a spherical geometry whose lapse contains independent inverse-radius terms through the fifth order. Free millicharged particles and neutral dark atoms provide microscopic response models through cold-plasma disp...

Equivalence-Principle Tests and Dark-Matter Constraints in Symmergent Gravity

We investigate whether the low-energy gravitational sector of symmergence can produce observable violations of the universality of free fall or account for dark-matter phenomenology. The quadratic-curvature term introduces a scalar degree of freedom, but its coupling through the...