The Interpretation of Quantum Mechanics and the Measurement Process by Peter Mittelstaedt download in pdf, ePub, iPad
Notice that no conscious observer need be involved. This is the orthonormality condition needed to interpret the squares of the wave functions as probabilities.
The vertical polarizer will absorb the horizontal photon completely. The particle path can not be observed. When we have only one photon at a time, we never get one-half of a photon coming through the polarizer. These two happen together, as the quantum states have become correlated with the states of the sensitive detectors in the classical apparatus.
And Bohr did not accept photons as being emitted and absorbed during quantum jumps until twenty years after Einstein proposed them - if then. These two are involved in the formation of microscopic objects like atoms and molecules, as well as macroscopic objects like galaxies, stars, and planets. There are two possibilities. These interpretations hope to restore the determinism of classical mechanics. But a coupling, even with a measuring device, is not yet a measurement.
The third novel idea of quantum theory is often considered the most radical. We can calculate the probabilities for each eigenvalue. Excited metastable states are poised to collapse when an electron or photon collides with the sensitive detector elements in the apparatus. We develop a quantum-mechanical treatment of macroscopic systems, especially a measuring apparatus, to show how it can create new information.