The observer effect in quantum: the case of classification

The observer effect in quantum physics states that observation inevitably influences the system being observed. Our proposed epistemic framework treats the observer as an integral part of sensory information processing within entangled quantum systems, highlighting the subjective and probabilistic aspects of observation and inference. Our study introduces a hierarchical model for fuzzy instance classification, which aligns sensory input with an observer's pre-existing beliefs and associated quantum probability-based truth values. Sensory data evolves via interaction with observer states, as described by the Lindblad master equation, and is then classified adaptively using positive operator-valued measures (POVM). Our parametrization employs measures of concurrent similarity and dissimilarity, facilitating perceptual associations and asymmetric cognition. The observer's position on a skeptic-believer spectrum modulates ambiguous matching of noisy perceptions. We show that sensory information becomes intricately entangled with observer states, yielding a wide array of probabilistic classification results. This framework lays the groundwork for a quantum-probability-based understanding of the observer effect, encouraging further exploration of quantum correlations and properties in cognitive processes.