Why "CPT" is the Universe's most unbreakable symmetry

"The ultimate goal of physics is to accurately describe, as precisely as possible, exactly how every physical system that can exist in our Universe will behave. The laws of physics need to apply universally: the same rules must work for all particles and fields in all locations and at all times."

"And yet, there's one fundamental, overarching symmetry that applies to not just all of these physical laws, but for all physical phenomena: CPT symmetry. And for nearly 70 years, we've known of the theorem that forbids us from violating it: the CPT theorem. Here's why it's so powerful, and why the CPT symmetry is truly unbreakable."

"Having predictive power, explicitly, means that if you know the initial conditions of your system and the laws that govern it, you can predict what the outcomes - or the relative probability of the set of possible outcomes - will always turn out to be."

Physics aims to describe how all physical systems behave with universal laws applicable to all particles, fields, locations, and times. Successful physical theories include quantum field theories describing fundamental interactions and General Relativity describing spacetime and gravitation. These theories must provide predictive power: given initial conditions and governing laws, outcomes or their probabilities can be predicted. Underlying all physical phenomena is CPT symmetry, a fundamental overarching principle. The CPT theorem, established nearly 70 years ago, forbids violation of this symmetry. CPT symmetry represents a powerful, unbreakable principle governing all physical laws and interactions.

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