The following is a link to a 1-hour lecture by Sean Carroll about QM
and the Everett Interpretation, followed by a 20-minute Q&A:
<
https://www.youtube.com/watch?v=nOgalPdfHxM>
The following is Carroll's take on some of the problems caused by the Copenhagen Interpretation:
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@20:29
So again, uniquely in the history of physics, we have two rules, two
sets of rules sorry, to describe quantum mechanics. One set of rules
for when you're not looking at it. Systems are described by wave
functions, the wave functions perfectly obey Schrodinger's equation.
Then when you measure them, a completely new set of rules takes force,
and again, that never happened before in physics. The wave function
will collapse to a particular value, it will look particle-like and
there's a probability that you get different measurement outcomes.
So this is known as the Copenhagen Interpretation. But people
disagree about what the Copenhagen interpretation actually says, so I
just call it the textbook version of quantum mechanics. I'm not
fooling you, for those of you who are not physicists. This is what we
teach our students at Johns Hopkins or Caltech or anywhere. This
is what we tell them about quantum mechanics. If they start asking
questions, we kick them out [audience laughter].
Ah hah, you laugh, nervous laughter. The reason why you should be a
little bit upset about this is because the textbook picture of quantum mechanics is *clearly* unacceptable as a fundamental theory of nature.
We'd like to think that quantum mechanics is the best most fundamental
most basic idea we have about how nature works, and yet we tell this
crazy story about what's going on.
@21:50
So let me highlight two ways in which this is unacceptable, and again
by unacceptable I don't mean false. I just mean clearly not the final
answer. Clearly there are some questions being left open here.
So the famous one is the measurement problem. So in those rules for
quantum mechanics we have "When You observe the system you get certain
things happening".
What does that mean? What counts as a measurement? Can a video
camera measure something? Can a mouse measure something? What about
a person who needs glasses, and they're not, they don't have their
glasses on? What if I just squint at the system? How quickly does it
happen? When does it happen? Why does it involve you know a
conscious kind of observer? And you can see how a whole book industry
about Quantum healing and Quantum yoga and Quantum leadership is going
to spring up in the aftermath of this, because this way of yoga and
Quantum leadership is going to spring up in the aftermath of this,
because this way of talking seems to put human agency at the center of
the universe, in a very non-Copernican way? Though whatever the
answers are the point is, the Copenhagen interpretation doesn't tell
us what the answers are. And that is too vague to be the final answer
to a theory of fundamental physics.
@23:06
Then there is the reality problem, which different people also have
different angles on. So we talk about the wave, the electron wave, or
the wave function, as we call it in the post-Schrodinger era.
What is that? Is it a real thing? Like an electromagnetic wave, it's
a real thing. You can measure it. You can put a little magnetometer
or a charge, and you could measure where the electric field magnetic
field are pointing. But we said you can't measure, you can't observe
the wave function. It's never what you see. Is it real? Or is it
just a way of making predictions about reality?
And you can see how it's going even further in the spooky woo-woo
directions. It's almost like we're bringing reality into existence by
thinking about it, or looking at it, or other bad things that lead to
bad movies and and bad TV shows, okay?
But it should be science. So we should think about this, and we
should be able to answer these questions. Let's think about the
reality. But let me admit that for all these questions, not everyone
agrees.
@24:06
So I wrote a op-ed piece for the New York Times where I say
"Nobody understands quantum mechanics and that's a problem". And I
expected at least a few of my colleagues to email me saying "What do
you mean? I understand quantum mechanics." And I was pleasantly
surprised it was only one colleague who did email me about that. But
the point is that people don't agree within the field. So even if one
of us is right there is no consensus among physicists about the
answers to these questions.
So from that, from to this point, to this in the talk I've been saying
things that are true. I hope I'll be saying things true in the
future, but I'm going to be more opinionated. I'm going to give you
my angle on it. It needs to be a six lecture series for me to give
you everybody else's angle on it, so you can invite them to give you
their pictures.
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--
You're entitled to your own opinions.
You're not entitled to your own facts.
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