2025/12/09 by Jiménez, Jose Beltrán, Bettoni, Dario, Brax, Philippe +2
Physics and Astronomy · #Cosmology and Gravitation Theories #Quantum Electrodynamics and Casimir Effect #Quantum and Classical Electrodynamics
paper · doi:10.48550/arxiv.2512.08865
We study finite size effects on the linear response of spherically symmetric objects in Born-Infeld (BI) electromagnetism and Dirac-Born-Infeld (DBI) scalar field theories. Previous works show that the linear response coefficients for a point-like source vanish for odd multipoles above the dipole, a feature that resembles the vanishing of Love numbers for black holes. This work goes beyond the point-like idealisation and considers a sphere of finite radius. We find that the vanishing of the linear response coefficients ceases as they acquire a correction due to the finite size of the object. This introduces a hierarchy between the even and odd multipoles of the response coefficients determined by the separation of scales between the radius of the sphere and the screening scale of non-linearities. From a phenomenological viewpoint, the hierarchy between the odd and even multipoles would give access to the screening scale and the object's radius by measuring the behaviour of the potentials at infinity.