It is true that the historical Copenhagen interpretation—the one developed by Bohr—is instrumentalist. But that’s no longer what people mean when they refer to the Copenhagen interpretation. Look at pretty much any introductory text on QM and the Copenhagen interpretation (or the “orthodox” interpretation) is presented as an objective collapse theory, with collapse being a physical process that takes place upon measurement.
As for your point 2, it just isn’t true that all collapse interpretations assume that collapse only takes place at the end of the experiment. Take GRW, for instance. It is a spontaneous collapse theory, where collapse is governed by a stochastic law. There is nothing in this law that prevents collapse from occurring midway through an experiment, or alternatively not occurring at any point in the experiment, not even the end.
Also, if collapse is supposed to take place only at the end of a measurement, how do objective collapse theories make sense of phenomena like the quantum Zeno effect, where measurement is taking place continuously throughout the course of the experiment?
Look at pretty much any introductory text on QM and the Copenhagen interpretation (or the “orthodox” interpretation) is presented as an objective collapse theory, with collapse being a physical process that takes place upon measurement.
That is perhaps a common misconception in popular science publications aimed at non-technical audiences, but I’m not aware that it’s prevalent in technical literature. Even if it was, that’s not a good reason to further the misuse of terminology.
As for your point 2, it just isn’t true that all collapse interpretations assume that collapse only takes place at the end of the experiment.
It doesn’t matter. All interpretations must agree with the predictions of the theory, at least in all the cases that have been practically testable so far. The experiment you proposed predicts the same results whether or not you shield the intermediate observer from decoherence. If your math predicts different results, then there must be some mistake in it.
Also, if collapse is supposed to take place only at the end of a measurement, how do objective collapse theories make sense of phenomena like the quantum Zeno effect, where measurement is taking place continuously throughout the course of the experiment?
It is true that the historical Copenhagen interpretation—the one developed by Bohr—is instrumentalist. But that’s no longer what people mean when they refer to the Copenhagen interpretation. Look at pretty much any introductory text on QM and the Copenhagen interpretation (or the “orthodox” interpretation) is presented as an objective collapse theory, with collapse being a physical process that takes place upon measurement.
As for your point 2, it just isn’t true that all collapse interpretations assume that collapse only takes place at the end of the experiment. Take GRW, for instance. It is a spontaneous collapse theory, where collapse is governed by a stochastic law. There is nothing in this law that prevents collapse from occurring midway through an experiment, or alternatively not occurring at any point in the experiment, not even the end.
Also, if collapse is supposed to take place only at the end of a measurement, how do objective collapse theories make sense of phenomena like the quantum Zeno effect, where measurement is taking place continuously throughout the course of the experiment?
That is perhaps a common misconception in popular science publications aimed at non-technical audiences, but I’m not aware that it’s prevalent in technical literature. Even if it was, that’s not a good reason to further the misuse of terminology.
It doesn’t matter. All interpretations must agree with the predictions of the theory, at least in all the cases that have been practically testable so far. The experiment you proposed predicts the same results whether or not you shield the intermediate observer from decoherence. If your math predicts different results, then there must be some mistake in it.
Why wouldn’t it make sense of it?