Concepts and Advances in Lorentz and CPT Violation*

Lorentz symmetry is a foundational aspect of relativity and a cornerstone of our best existing description of nature at the fundamental level. Minuscule observable violations of Lorentz symmetry and its concomitant CPT symmetry could arise from an underlying theory that unifies quantum physics with gravity at the Planck scale. The corresponding effects at attainable energies are described by a theoretical framework known as the Standard-Model Extension, which predicts exotic experimental signals in a variety of systems. Precision measurements searching for Lorentz and CPT violation are ongoing and have already achieved Planck-scale sensitivities in certain regimes. This talk outlines key concepts and advances in the subject, along with recent transformational developments that offer novel paths for experimental and theoretical exploration.