The recent thread concerning "qm texts other than Copenhagen"
struck me as a "good news / bad news" story.
The good news is that everybody _should_ be skeptical of
the Copenhagen "interpretation" of QM.
The bad news is that looking for a "deterministic"
interpretation is a step in the wrong direction. Indeed
looking for any kind of "interpretation" is the wrong
way to go.
=======
Constructive suggestion: If you want to know what's going
on in this area, you should ask about "quantum measurement"
and about "decoherence".
To say the same thing in less constructive terms, you
will have a hard time finding the right answer by googling
for "Copenhagen" or "interpretation" or "collapse" ...
for the same reason that you will have a hard time finding
out about chemistry by googling for "phlogiston". It's
passé. Modern chemists don't mention phlogiston, not
even as a contrast to what they are doing. They talk
about what they are doing, not what they are not doing.
Modern physicists speak in terms of "quantum measurement"
and "decoherence". They talk about what they are doing,
not what they are not doing. That's why I changed the
"Subject:" line of this thread.
With some exceptions, people tend to talk about the
"interpretation" of physics when they don't understand
the physics. In particular, Bohr did not understand how
to connect quantum mechanics to classical physics, so
he came up with an "interpretation" that concealed the
problem. It was a brilliant short-term tactic, but not
a good long-term strategy. It's like using duct tape
to close a sucking chest wound. It's better than nothing,
but it is not a viable long-term solution.
In an introductory course, the options are, in order
of declining preference:
a) There are plenty of QM books that don't mention
the "interpretation" business at all. This is as
it should be. If you want to say a few words about
quantum measurement, that's fine. If you are tempted
to talk about "interpretation" in general or
"Copenhagen" in particular, resist the temptation.
b) You could use a book that mentions the Copenhagen
"interpretation" and just skip that part.
c) You can find books that tout this-or-that hidden
variable theory, i.e. "deterministic" models of QM.
This is a step in the wrong direction. As a rule,
the more time spent discussing "interpretation"
the worse off you are. More to the point: every
hidden variable theory I've seen is provably wrong.
(Maybe someday somebody will come up with a
"deterministic" model of QM, but I'm not holding
my breath. It is hard to imagine how any hidden
variable theory could satisfy the Bell inequalities.)
=============
At the next level of detail: according to modern
thinking (in contrast to Bohr's thinking) there is
only one universe and its behavior is governed by
the laws of quantum mechanics. The so-called
"classical universe" is merely an approximation,
i.e. the _classical limit_ of the QM behavior.
It is important to be able to take the classical
limit correctly. Bohr correctly recognized that
this was important ... but he didn't know how to
do it correctly. In the years since then, we have
gotten much smarter about how to do this.
At the introductory level, the answer here is the
same as the answer in last week's thread about
"light interference and energy preservation".
The quantum mechanical (wave mechanical) answer
is that sometimes one and one makes zero, and
sometimes one and one makes four, but _on average_
one and one makes two. The average over all
phases is the _incoherent_ answer, i.e. the
classical answer.
In an introductory course, you don't need to say
more than this about decoherence and quantum
measurement. It should suffice to tell students
that the QM equations of motion get the right
answer. No "interpretation" is required. The
details get rather complicated when we apply
the equations to something as complicated as a
voltmeter where the input is quantum-mechanical
and the output is (for all practical purposes)
classical ... but if you chase down all the
details everything works out OK.
In particular, you should not delve into the
details unless/until the students are familiar
with density matrices ... and also fully up to
speed on thermodynamics, including the mathematical
foundations thereof (multi-dimensional calculus,
probability/statistics, et cetera). It also
helps if they know a little bit of quantum field
theory.
If you want the next level of detail on all this,
I recommend:
Wojciech Hubert Zurek : "Quantum Darwinism" http://arxiv.org/abs/0903.5082