QBism and the Greeks: why a quantum state does not represent an element of physical reality

TL;DR

This paper explains how QBism interprets quantum states as subjective beliefs rather than physical elements, contrasting it with hidden-variable theories and exploring its explanation of quantum correlations.

Contribution

It clarifies QBism's perspective on quantum states, contrasting it with hidden-variable models, and connects QBism to historical ideas from Schrödinger.

Findings

QBism treats quantum states as personal probabilities.

It contrasts QBism with hidden-variable theories.

QBism offers an agent-centered explanation of quantum correlations.

Abstract

In QBism (or Quantum Bayesianism) a quantum state does not represent an element of physical reality but an agent's personal probability assignments, reflecting his subjective degrees of belief about the future content of his experience. In this paper, we contrast QBism with hidden-variable accounts of quantum mechanics and show the sense in which QBism explains quantum correlations. QBism's agent-centered worldview can be seen as a development of ideas expressed in Schr\"odinger's essay "Nature and the Greeks".