Re: Understanding Schrodinger's cat.


"Igor" <thoovler@xxxxxxxxxx> schreef in bericht
news:1183398328.634913.103190@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jul 2, 12:20 pm, "Nicolaas Vroom" <nicolaas.vr...@xxxxxxxxxx>
wrote:

Why do you call this effect a superposition ?

Because that's how it is defined. According to the Copenhagen
interpretation, all possible solutions to the appropriate quantum wave
equations are in full linear combination, or superposition, until an
observation is made. Once an observation has been made, one
particular state is realized.

Suppose I shuffle a card deck,
I place them face down in front of you
and I point my finger to one of them
and I ask you is that card red or black
Before YOU look is that card also in
a superposition of states red vs black ?

Any way what we are discussing is a radioactive sample
in which many atoms can decay in a certain period of time.
That means the sample can decay many times.
Of course you do not know which paricular atom will decay.

This has absolutely nothing to do with what Schroedinger was trying to
say. His thought experiment was about the superposition of the states
of decay vs nondecay.

decay vs nondecay of what ?
one specific atom
or the whole sample which contains thousands of atoms which can decay.
(and which will decay in due time)

You learn that how longer you wait the higher the chance is that
the cat is dead.
That is all what you can learn.
Nothing about superposition.

True, but again, it's not relevant to what Schroedinger was trying to
say. And that was what you were asking about.

You can also make the box from glas. The result will be the same.

Not according to the Copenhagen interpretation, which essentially says
that things don't happen (in terms of a particular state being chosen
out of superposition) until you observe them.

Do you mean that according to the Copenhagen interpretation
the result will not be the same ? i.e. statistically relevant different
(500 dead versus 500 alive in a box of steel
versus 499 dead versus 501 alive in a box of glas is the same)

So the wave function
would just collapses sooner for a transparent box because you wouldn't
have to open it to make an observation.

When ?
When the cat dies ?
and what happens if you open the steel box and the cat is not dead ?

Does this test tells us something about the concept of superposition ?
Before you want to answer that question you first have to explain
what superposition is.
IMO the test does not require the concept of super position
as such it tells us nothing about superposition.

Many people misunderstand what Schroedinger was actually trying to
say. Schroedinger's original thought experiment put the cat's fate in
the same simultaneously superposed states that the radioactive decay
had had quantum mechanically.

Radio active decay is a concept described by half-life time.
which is specific for the radio active sample (atom) involved.
If the half-life time is 1 hour than if you place the cat in the box
for 30 minutes you have a 50% chance that the cat comes out
alive.
There is no superposition of states involved
(as far as I can see)

But there is. Half life is only a statistical concept spread over
many many atoms. Individual atoms will not have a half life. But
they do have a wave function governing radioactive decay, which is
nothing more than the emission of a particular particle. In classical
physics, the atom either emits the particle or it doesn't. It's not
so simple in QM, where the solution of the wave equation can have more
than one component that remain in superposition of possible states
until observed.

Assuming that that is correct the question again is when.
Suppose the alpha particle released, rings a bell is that not
the moment ?
Suppose there are two observers
one sees the cat first and calls: the cat is dead
what about the second observer ?

Nicolaas Vroom
http://users.pandora.be/nicvroom/


.

Relevant Pages

  • Re: Understanding Schrodingers cat.
    ... in the box the cat is both alive and dead. ... See John Gribbin "In search of schrodinger's cat" page 203. ... Why do you call this effect a superposition? ... That means the sample can decay many times. ...
    (sci.physics)
  • Re: keeping score
    ... that for a thin enough slice of matter, the proportion of ... Exactly the same treatment can be applied to radioactive decay. ... Radioactive atoms decay randomly. ...
    (talk.origins)
  • Re: keeping score
    ... that for a thin enough slice of matter, the proportion of ... Exactly the same treatment can be applied to radioactive decay. ... Radioactive atoms decay randomly. ... that we saw in the case of light attenuation. ...
    (talk.origins)
  • Re: keeping score
    ... that for a thin enough slice of matter, the proportion of ... Exactly the same treatment can be applied to radioactive decay. ... Radioactive atoms decay randomly. ...
    (talk.origins)
  • Re: keeping score
    ... that for a thin enough slice of matter, the proportion of ... Exactly the same treatment can be applied to radioactive decay. ... Radioactive atoms decay randomly. ...
    (talk.origins)
Quantcast