Maximum Entropy and Acausal Processes: Astrophysical Applications and Challenges

Abstract

In Newtonian physics, if we know the state of the world at some moment of time, then we can precisely predict the state of the world at all future times. In this sense, Newtonian physics is deterministic. In modern physics (starting with quantum mechanics), theories are usually non-deterministic in the sense that even if we know exactly the initial state of the world, we cannot uniquely predict the future state of the world. In quantum mechanics (and in most modern quantum-based physical theories), the best we can get is probabilities of different future states. In this sense, in the majority of modern physical theories, uncertainty is of statistical nature.