Quantum Bayesianism (QBism)

Quantum Bayesianism, or QBism, is an interpretation of quantum mechanics that views the mathematical probabilities in quantum theory as expressions of an individual's personal beliefs about the outcomes of measurements, rather than objective properties of particles. It emphasizes that quantum states reflect an observer's knowledge and expectations, which are updated upon gaining new information. QBism treats measurement outcomes as personal experiences, highlighting the role of the observer's perspective in understanding quantum phenomena. This approach aims to reconcile quantum mechanics with a subjective view of knowledge, emphasizing that the theory provides a framework for each person to manage their expectations about the behavior of quantum systems.