The discussion centers on the Copenhagen interpretation of quantum mechanics (QM) and the definitions of "measurement" and "observer." It establishes that while a sentient observer is traditionally considered necessary for measurement, non-sentient classical devices can also fulfill this role, as they are not quantum themselves. The conversation highlights the measurement problem, where the act of observation collapses a particle's wave function, and explores alternative interpretations like Bohmian Mechanics and Many-Worlds. Ultimately, the participants express a desire for clarity on how larger units of matter can exist without constant observation, indicating a fundamental issue within the Copenhagen framework.
PREREQUISITESStudents and researchers in quantum mechanics, physicists exploring interpretations of QM, and anyone interested in the philosophical implications of measurement and observation in quantum theory.
atyy said:OK, perhaps it is just semantics.
bhobba said:That's all much of this is IMHO.
Jimster41 said:It is an intriguing open question whether the linearity of quantum mechanics extends into the macroscopic domain.
bhobba said:The key point of assuming its a proper mixture is there is some process that makes it a proper mixture - that linearity breaks down is one way to explain it - but not the only one.
Just want to mention that @bhobba (as well as others) pointed me to that paper.atyy said:I'm not sure. If you agree with my analogy with GRW/CSL versus Copenhagen Continuous Measurement, then in the former we can have a state of the universe including the observer (ie. quantum mechanics without observers), while in the latter there is no meaning to the state of the universe.
Also, GRW and CSL and Bohmian Mechanics, as I understand, do eventually lead to deviations from quantum mechanics, which I think can be in principle tested (maybe even in practice as discussed by the link http://arxiv.org/abs/1410.0270 posted by Jimster41).