Ellipticity weakens chameleon screening

Burrage, Clare; Copeland, Edmund J.; Stevenson, James

Abstract

The chameleon mechanism enables a long-range fifth force to be screened in dense environments when nontrivial self-interactions of the field cause its mass to increase with the local density. To date, chameleon fifth forces have mainly been studied for spherically symmetric sources; however, the nonlinear self-interactions mean that the chameleon responds to changes in the shape of the source differently to gravity. In this work we focus on ellipsoidal departures from spherical symmetry and compute the full form of the chameleon force, comparing its shape dependence to that of gravity. Enhancement of the chameleon force by up to 40% is possible when deforming a sphere to an ellipsoid of the same mass, with an ellipticity ∼0.99.

Citation

Burrage, C., Copeland, E. J., & Stevenson, J. (2015). Ellipticity weakens chameleon screening. Physical Review D, D91(6), Article 065030. https://doi.org/10.1103/PhysRevD.91.065030

• Journal Article Type: Article
• Acceptance Date: Mar 25, 2015
• Publication Date: Mar 25, 2015
• Deposit Date: Apr 20, 2017
• Publicly Available Date: Apr 20, 2017
• Journal: Physical Review D
• Print ISSN: 2470-0010
• Electronic ISSN: 2470-0029
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: D91
• Issue: 6
• Article Number: 065030
• DOI: https://doi.org/10.1103/PhysRevD.91.065030
• Public URL: https://nottingham-repository.worktribe.com/output/746823
• Publisher URL: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.065030
• Contract Date: Apr 20, 2017