Experimental testing of the copenhagen quantum theory interpretation
I have made no bones of the fact that I believe that the resolution of
the puzzles of quantum theory must lie in our finding an improved
theory. Though this is perhaps not the conventional view, it is not
an altogether unconventional one. (Many of quantum theories
originators were also of such a mind. I have referred to Einsteins
views. Schroedinger (1935), de Broglie (1956), and Dirac also regarded
the theory as provisional.)
Roger Penrose
Welcome to the Solvay conference of 1927
Who was right – Einstein or Bohr?
They were both wrong!
Schrödinger’s
famous
cat experiment demonstrates a remarkable problem.
For Schrödinger, his cat experiment exposed the absurdity of the Copenhagen
interpretation since for him an object the size of a cat is either
„really” dead or “really” alive. According to
Schrödinger, an uncertain transient state of a cat between
“dead” and “alive” is physically meaningless.
According to Bohr, the issue of the cat’s condition before measurement, i.e.
before opening the container where the cat is located, does not
really occur, since quantum theory according to the Copenhagen
interpretation does not describe the world as it “really”
is but who it portrays itself to our measuring instruments.
Quantum theory does
not describe the “real” world but only the result of
measurements. Accordingly it is impossible to make statements about
what condition the cat is in before the container is opened. But by
opening the container, a measurement takes place, thus a collapse of
the wave function (which describes the condition of the cat) and
only then is a decision on “dead” or “alive”
given.
The problem of the cat experiment lies precisely here:
Before measurement, no statement about the cat’s condition can be
made. But after measurement, no statement is possible about
the condition of the cat before measurement either for the
same reason (i.e as the cat “objectively” or “really” is).

Apparently no empirical criterion is thus even imaginable for an
objective reality which does not include an intrusive measurement and in this way a
reality independent of the measurement itself (i.e. objective) cannot be proven.
On the
other hand, I have found a possibility of circumventing these
special difficulties and of taking correction of the Copenhagen
interpretation forward to a unambiguous yes/no decision in an
experiment.


Schrödinger’s cat is only found in an uncertain state between
“dead” and “alive” until it is measured. For quantum theory
describes, according to Bohr, not the “real” world but only our knowledge
of the world. According to this, the collapse of the wave function signifies only a
modification of our state of information or of our knowledge by means of measurement.
Consequently, no collapse of the wave function is possible without modification of
our knowledge!
Until now, attempts were made to rebut the Copenhagen interpretation of quantum
theory by measuring without disturbing the system. This has failed.
For this reason, I wish to pursue the opposite approach, which is to disturb a system
without measuring it, i.e. to bring about a collapse of the wave function without
changing our knowledge of the system.
My experiment disturbs the system (i.e. prevents an interference) without
measuring which path the particle takes. But without measurement, i.e. without
a gain in knowledge according to Bohr a collapse of the wave function or
prevention of interference is excluded, since the wave function constitutes nothing
but our information or our knowledge of the system.
If this knowledge is not modified, then the wave function cannot be modified
either!
But if it does so, then the wave function not only constitutes our knowledge
of the world, but the world itself. Hence, the collapse of the wave function would be
an objective phenomenon, as Penrose proposes, since it would occur independent of any
measurement.