The concept of true randomness in quantum mechanics is a fascinating and complex topic. In simple terms, here's an overview of how we currently understand randomness in the context of quantum mechanics:
In classical physics, randomness is often associated with our lack of knowledge or understanding of the underlying mechanisms governing a system. However, in quantum mechanics, there is an inherent randomness that is not merely a result of hidden or unknown factors.
Quantum mechanics describes the behavior of particles at the microscopic level, such as electrons or photons. According to quantum theory, these particles do not have well-defined properties, such as position or momentum, until they are measured. Instead, they exist in a superposition of multiple possible states, with each state having a certain probability of being observed when measured.
When a measurement is made on a quantum system, the act of measurement "collapses" the superposition of states into a single outcome, chosen randomly based on the probabilities associated with each state. This randomness is a fundamental characteristic of quantum mechanics and is known as intrinsic or true randomness.
Experimental observations and rigorous testing of quantum systems have consistently shown that the outcomes of certain measurements cannot be explained by any classical theory that relies on hidden variables or deterministic processes. This indicates that the randomness observed in quantum systems goes beyond our current understanding of underlying mechanics.
Furthermore, various experiments, such as Bell's theorem and tests of Bell inequalities, have provided evidence supporting the notion of non-locality and non-determinism in quantum mechanics. These experiments suggest that the behavior of entangled particles cannot be explained by classical deterministic models, reinforcing the idea of genuine randomness in quantum systems.
While our understanding of the underlying mechanisms behind quantum randomness is still an active area of research, the evidence from experiments and the mathematical formalism of quantum mechanics strongly support the existence of true randomness in the quantum world.