Speaker: Dr. Daniela Saadeh
Title: Fifth-Force Screening around Extremely Compact Sources
Abstract: The phenomenology of dark energy may be explained by an extra scalar particle mediating a fifth force at cosmological scales. However, stringent limits on the existence of extra forces have been placed by solar-system experiments: viable models must therefore be able to screen (i.e. suppress) the fifth force in environments where it is known to be small.
Several screening mechanisms have been proposed. However, progress in understanding their behaviour has been hindered by the complexity of the field equations involved, which are nonlinear in nature and characterised by a large hierarchy of scales. This is especially true for point-like sources, like atoms or neutrons, which are used to constrain screening in terrestrial laboratory tests.
In this talk, I will focus on chameleon-like screening and examine the behaviour of the fifth force in the limit that the source becomes extremely compact. To do so, I will use the finite element method to solve for the full behaviour of the scalar field as the size of the source shrinks, for spherically and cylindrically symmetric sources.
Several screening mechanisms have been proposed. However, progress in understanding their behaviour has been hindered by the complexity of the field equations involved, which are nonlinear in nature and characterised by a large hierarchy of scales. This is especially true for point-like sources, like atoms or neutrons, which are used to constrain screening in terrestrial laboratory tests.
In this talk, I will focus on chameleon-like screening and examine the behaviour of the fifth force in the limit that the source becomes extremely compact. To do so, I will use the finite element method to solve for the full behaviour of the scalar field as the size of the source shrinks, for spherically and cylindrically symmetric sources.
Meeting Recording:
https://port-ac-uk.zoom.us/rec/share/yRerJglD7mSKNeCr_206XueBKpIOVksWQ550cpR2FkUM-Qwg_QFvnjA2V3Yuya5a.KvFKqUfpnRZpHJNa
