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Full-Text Articles in Physical Sciences and Mathematics

Tests Of Lorentz Symmetry In The Gravitational Sector, Aurélien Hees, Quentin G. Bailey, Adrien Bourgoin, Hélène Pihan-Le Bars, Christine Guerlin, Christophe Le Poncin-Lafitte Jun 2019

Tests Of Lorentz Symmetry In The Gravitational Sector, Aurélien Hees, Quentin G. Bailey, Adrien Bourgoin, Hélène Pihan-Le Bars, Christine Guerlin, Christophe Le Poncin-Lafitte

Quentin Bailey

Lorentz symmetry is one of the pillars of both General Relativity and the Standard Model of particle physics. Motivated by ideas about quantum gravity, unification theories and violations of CPT symmetry, a significant effort has been put the last decades into testing Lorentz symmetry. This review focuses on Lorentz symmetry tests performed in the gravitational sector. We briefly review the basics of the pure gravitational sector of the Standard-Model Extension (SME) framework, a formalism developed in order to systematically parametrize hypothetical violations of the Lorentz invariance. Furthermore, we discuss the latest constraints obtained within this formalism including analyses of the …


Computing Periods Of Nonlinear Hamiltonian Systems In The Two-Body Problem Of Celestial Mechanics, Maia Powell Apr 2019

Computing Periods Of Nonlinear Hamiltonian Systems In The Two-Body Problem Of Celestial Mechanics, Maia Powell

Ursidae: The Undergraduate Research Journal at the University of Northern Colorado

The two-body problem in celestial mechanics models the gravitational relationship between two celestial bodies and predicts their corresponding orbital paths. Isaac Newton proposed a two-body problem that accurately modeled systems whose rotating mass exhibited a perfectly elliptical orbit. Albert Einstein’s theory of general relativity expanded the original two-body problem to include systems with irregular orbits. Einstein’s model, a nonlinear Hamiltonian system, produces solutions that are elliptic functions. Though we know that elliptic solutions exist, their complexity makes them inaccessible. Current research explores potential properties of such irregular systems represented by Einstein’s model in an effort to better understand and predict …