Quantum Bayesianism
Quantum Bayesianism, also known as QBism, is an interpretation of quantum mechanics that places emphasis on subjective probabilities and Bayesian reasoning. It was developed by Christopher Fuchs and his collaborators as an attempt to address the conceptual and interpretive issues of quantum theory.
In QBism, the central idea is that quantum mechanics provides a framework for updating personal probabilities based on subjective beliefs and experiences. It treats quantum states as personal probabilities representing an agent's knowledge and beliefs about the system being observed. Quantum probabilities are seen as degrees of belief rather than objective properties of the system.
According to QBism, the wave function is not an ontological entity describing the state of a system, but rather a representation of an agent's personal probabilities or degrees of belief. Measurement outcomes are viewed as personal experiences that update an agent's probabilities according to Bayesian inference rules.
QBism places a strong emphasis on the role of the observer or agent in quantum theory. It suggests that the fundamental task of quantum mechanics is to provide a framework for an agent to update and revise their probabilities based on their experiences. It places the agent at the center of the interpretive framework and considers the agent's beliefs and actions as essential components of the theory.
QBism shares some similarities with the Bayesian interpretation of probability theory, which views probabilities as subjective degrees of belief rather than objective frequencies. It also has connections to the subjective interpretation of probability within statistics and the broader Bayesian approach to reasoning and inference.
It's important to note that QBism is a relatively recent interpretation of quantum mechanics and remains a topic of ongoing research and debate within the field. While it offers a novel perspective on the role of subjectivity and probabilities in quantum theory, it is not universally accepted and continues to be scrutinized and refined by researchers in the field of quantum foundations.
