What do we know about Lorentz invariance?

Area of Science:

• * Theoretical physics
• * Quantum gravity
• * Particle physics

Background:

• * Planck-scale physics offers a window into quantum gravity.
• * Testing Planck-scale physics is achievable with current technology by searching for spacetime symmetry violations.
• * The Standard-Model Extension (SME) framework was developed to study deviations from Lorentz and CPT symmetry.

Purpose of the Study:

• * To review the fundamental concepts of Lorentz and CPT symmetry.
• * To outline the structure and components of the gravitational SME framework.
• * To present recent experimental and theoretical findings in the field.

Main Methods:

• * Review of theoretical frameworks for spacetime symmetry.
• * Analysis of the gravitational Standard-Model Extension (SME) structure.
• * Compilation of recent experimental tests and theoretical developments.

Main Results:

• * The development of the gravitational SME framework has spurred numerous tests of Lorentz symmetry.
• * Significant theoretical interest has been generated in the study of Lorentz and CPT symmetry.
• * Existing technology enables the search for Planck-scale physics through symmetry violation.

Conclusions:

• * The gravitational SME provides a robust framework for probing fundamental symmetries.
• * Experimental and theoretical research in this area is rapidly advancing.
• * The search for spacetime symmetry violation is a key avenue for testing Planck-scale physics.