Crossword: Copenhagen interpretation

The theme of this puzzle is the observational collapse of a quantum wavefunction into a single state. The shaded squares each represent two potential “states”—that is, they have two simultaneous solutions—except where the clue to 42-Across collapses the wavefunction in the circle into one of the two choices. (Note: The interactive puzzle shows only one of the two solutions. The downloadable PDF on this page includes both solutions.)

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ACROSS

DOWN