
How Schrödinger’s Cat Became Such a Violent Fable - bilifuduo
http://nautil.us/issue/41/selection/how-einstein-and-schrdinger-conspired-to-kill-a-cat
======
M_Grey
Two deeply unrelated quotes that I find apply here. The first is from a
segment on a Christmas special of the British radio comedy panel show, _The
Unbelievable Truth_ , and the second is Einstein's.

 _" Schrodinger, philosophic science whiz popped a kitty in his a pretty kitty
and says ‘If you open the box, the 'lectric shocks.’ 'Don’t touch the box… the
cat is now a paradox.’ 'Both dead and alive is the feline situation’ 'But its
status will be changed by the act of observation’ The main thing that we learn
from that: Schrodinger did not like cats."_ -Rufus Hound

 _“[I advocate] that one conceives of the psi-function [i.e., wavefunction]
only as an incomplete description of a real state of affairs, where the
incompleteness of the description is forced by the fact that observation of
the state is only able to grasp part of the real factual situation. Then one
can at least escape the singular conception that observation (conceived as an
act of consciousness) influences the real physical state of things; the change
in the psi-function through observation then does not correspond essentially
to the change in a real matter of fact but rather to the alteration in our
knowledge of this matter of fact.”_ -Albert Einstein

~~~
wyager
In said quote, Einstein advocates hidden variable theory, which was disproven.
[https://en.m.wikipedia.org/wiki/Bell_test_experiments](https://en.m.wikipedia.org/wiki/Bell_test_experiments)

I would strongly advise people who do not have extensive tuition in Quantum
Mechanics to refrain from speculating about the consequences of QM. I have
been taking QM classes for several years now, and the most valuable thing I've
learned is that almost everyone's understanding of QM is based on bad ad-hoc
analogies, and it takes years of study to progress to gradually less ad-hoc
analogies. Different mathematical models inform different "interpretations" of
QM. If you can't tell the difference between a rigged and non-rigged Hilbert
space, you certainly don't have enough background to speculate on classical
QM, and I'm not at the point where I could even tell you the background
required to speculate on modern QFT.

~~~
jostylr
Local hidden variable theories are not possible, but any local theory is not
possible, assuming definite outcomes of experiments (many worlds might be
considered local, but there is no definite outcome).

Non-local hidden variable theories are quite possible, do quite well in
explaining a number of facets of QM, and, in fact, inspired Bell's work.

Nevertheless, Einstein certainly was no fan of the non-locality though he did
not know of Bell's argument, of course.

~~~
tiglionabbit
Non-locality can't be right though, since locality is defined by the speed of
light, and nobody will tell you that sending information faster than the speed
of light is possible.

Many worlds it is, then.

~~~
wyager
Many worlds isn't the only alternative. The "cleanest" (i.e. least magical)
proposed solution I know of is einselection, which gives us emergent behavior
of the schroedinger equation that looks kind of like many worlds and kind of
like "ideal" non-unitary collapse, but doesn't posit any "unobservable" or
"magical" processes unlike many worlds or Copenhagen.

~~~
jostylr
You have to be clear about what is real in the theory. Many worlds
presentations often suffer from this as they often talk about splitting
universes, whatever that would mean.

A nice version which might coincide with what is in mind for einselection is
to take the wave function and integrate it out to get a mass density on three
space. This mass density will the various different "worlds" present in it by
means of the evolution; any given time will not tell us what belongs to which
world, but as time evolves, we can see which pictures correspond to which
ones, like fuzzy tv sets. See
[https://arxiv.org/pdf/0903.2211.pdf](https://arxiv.org/pdf/0903.2211.pdf)

~~~
M_Grey
There isn't much to recommend any of the many 'Interpretations' of QM, and if
you deal with people involved in using it for their jobs, they tend to adhere
to a "shut up and calculate" interpretation.

After all, why construct an ontology based on what is clearly not complete at
all energy scales? Still, where there are gaps, people will "theorize".

~~~
jostylr
It is all a matter of what you want out of science. Some people, such as
myself, enjoy having a narrative about how the universe works consistent with
experiments. This is both satisfying and useful in finding new directions to
push or ways to solve problems (such as a recent attempt to solve the
divergences in QFT by using boundary conditions appropriate for particle
flows:
[https://arxiv.org/pdf/1506.00497.pdf](https://arxiv.org/pdf/1506.00497.pdf)).
If you have just quantities to compute, but have no idea what those quantities
represent in reality, it is hard to see how one can think of that as
understanding how the universe works.

It is not clear why having a "complete" theory would change one's position on
ontology. It is either important or it is not to a person, just as some people
love playing with big machinery and only care about models in as far as it
enables them to do that. Others really do not care about big machinery except
as it produces potential data to suggest new models or discard the old. Why
should one make a judgement about that?

~~~
M_Grey
If what you want out of science is a narrative with no clear basis in reality,
why bother with science?

~~~
jostylr
It certainly has a basis in reality. The story needs to be consistent with
what we know, at least in the realm that it claims to give sense to. Science
is not about getting the absolute truth, it is about getting information and a
story consistent with what we know to be true, often with caveats about where
the story applies.

And, of course, you can deny ontology all you like, but everyone operates with
one in their mind. It is impossible to do interact with reality and to use
equations without some internal assumption of an ontology, however vague and
unexamined it might be. It is just that the "shut up and calculate" crowd does
not want to discuss it, much like how "very religious" people often do not
want to talk about their religion. They are simply not interested in examining
stuff that may challenge their world views. But it doesn't mean they don't
have an underlying belief.

It is similar to, paraphrasing Bell, how solipists buy life insurance.

The real point of science is to question our assumptions and obtain a better
understanding, often contradicting what we thought was true. In order to do
that, one has to look at what one believes is true. This is what the
investigation of different ontologies is doing. But, as I said, many are not
interested in pursuing that line of thinking and that's fine.

But it is not fine to say it should not be pursued at all or to imply it is
less important or noble. Different aspects of understanding should be pursued
by those who find those aspects enjoyable to pursue.

------
wodenokoto
I've known about schrödingers cat for years, though my physics background is
just high school + the odd popular science book.

It wasn't until a few months ago that I learned on reddit that it isn't an
explanation of quantum physics, but a critique.

This explains why the cat isn't an observer that causes the wave function to
collapse or why the cat isn't dead or alive, but we as outsiders can't know
and thus simply think of it as both until we open the box.

------
cyberferret
I first came across the story when reading Douglas Adams' "Dirk Gently's
Holistic Detective Agency" many decades ago. It spurred me to learn a bit more
about philosophic science.

Now it appears that every man and his cat spouts on about Mr. Schrodinger and
his hapless kitty at the drop of a decayed subatomic particle... Verschränkung
has become pop culture...

------
erikpukinskis
Has anyone written code that can do quantum decoherence of radiation in an
OpenGL fragment shader?

Edit: I'm imagining some kind of subset of QuTiP that could calculate photon
(electron?) states from a wave function, ported to GLSL.

Edit 2: Maybe a Born probability that would draw the interference pattern from
the double slit experiment? Or a reduced density matrix or something? The word
"matrix" makes me think it might be amenable to a GPU, but I don't really know
GLSL or quantum physics.

------
diyseguy
Schrödinger's cat was a zombie

