Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Hood on 05/05/2009 20:30:02

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: Hood on 05/05/2009 20:30:02

R Hood  asked the Naked Scientists:
   
In describing the Schrödinger's cat thought experiment, it is just assumed we understand that the quantum level cat is both alive and dead simultaneously up to the time we observe it. But how?

How can things be in two places at the same time at the quantum level? or please explain how quantum superpositions work?

Enjoy the show (http://www.thenakedscientists.com/HTML/podcasts/)
Rob
Melbourne

What do you think?

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: DoctorBeaver on 06/05/2009 10:04:05

Erwin Schrodinger came up with the cat thought experiment as a way of illustrating what he saw as absurdities in trying to apply the Copenhagen Interpretation to the everyday world. The Copenhagen Interpretation was a particular interpretation of quantum physics (no need to go into the details of it here).

As for something being in 2 places at once, that is just how QT represents things; it doesn't necessarily mean something actually is in 2 places at once. It's concerned with what happens up to the point of obversation. QT says there is no way of knowing the state of something until it is observed or measured. All possible states must be considered with varying degrees of probability.

In the case of Schrodinger's cat there are 2 possible states, each with equal probability. As there is no way of knowing the condition of the cat before the box is opened it must be taken as a 50% probability that the cat is alive and 50% that it is dead.

HERE (http://www-staff.it.uts.edu.au/~simmonds/Sophy/superposition.htm) is an interesting little snippet.

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: syhprum on 10/05/2009 10:53:55

I feel that the probability that the cat is dead is much greater than that it is alive.
If the radioactive emitter has been identified as such it must have emitted at least one particle by now.

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: lyner on 10/05/2009 12:42:03

Doesn't it all depend on the half life?

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: Bored chemist on 10/05/2009 16:12:50

I think the experiment was first proposed in about 1935; what's the half life of a cat?

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: lyner on 10/05/2009 23:52:01

How long does the other half live?

Title: Is Schrodinger's cat alive and dead at the same time?
Post by: Madidus_Scientia on 11/05/2009 01:31:36

Do cats have 9 half-lives?