Observation: more decoherence or interference?

Loren Booda
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Does observation decohere the object, or also interfere with the observer, to manifest macroscopic reality? A classical measurement might result either from equilibrium of object phase itself or of phase difference relative to the observer.

How, then, do these large-scale effects of object assimilation compare to those of interaction with the observer? What you sense directly - is it so because of its own decohered aggregate quantum nature, or because that other aggregate decohered along with you the observer?
 
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NO, decoherence isn't to do with observation, a large quantum system will suffer decoherence before any measuremnt is made on it. It's just the tendency of very large quantum systems to behave classically.
 


The concept of observation and its role in manifesting macroscopic reality is a complex and debated topic in quantum mechanics. There are different interpretations and theories that attempt to explain the relationship between observation and the behavior of quantum systems.

One possible interpretation is that observation causes decoherence, which is the process by which a quantum system becomes entangled with its environment and loses its quantum coherence. In this view, the act of measurement or observation forces the quantum system to collapse into a definite state, leading to the appearance of a classical reality.

On the other hand, some theories propose that observation not only decoheres the object, but also interferes with the observer. This means that the act of observation itself is a quantum process and can influence the behavior of the observer and the observed system. This idea challenges the traditional view of an objective reality independent of the observer.

The concept of equilibrium is also important in understanding the role of observation in manifesting macroscopic reality. In classical measurement, the result is determined by the equilibrium state of the object itself or the phase difference between the object and the observer. This suggests that the observer plays a crucial role in the measurement process and that the measurement outcome is not solely determined by the object.

In terms of large-scale effects, it is difficult to compare the effects of object assimilation and interaction with the observer. Both are important factors in the manifestation of macroscopic reality and cannot be separated. What we sense directly is a result of both the object's decohered quantum nature and the observer's interaction with it.

Overall, the role of observation in manifesting macroscopic reality is a complex and ongoing area of research in quantum mechanics. It is important to consider both the object and the observer when trying to understand the behavior of quantum systems.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
If we release an electron around a positively charged sphere, the initial state of electron is a linear combination of Hydrogen-like states. According to quantum mechanics, evolution of time would not change this initial state because the potential is time independent. However, classically we expect the electron to collide with the sphere. So, it seems that the quantum and classics predict different behaviours!
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