Law of Nuclear decay?

1. Jan 3, 2007

pivoxa15

Radioactive decay is normally characterised by 'the rate of decay is linearly proportional to the number of nuclides avaliable'. i.e dN/dt=-aN (a>0)

How correct is this law? Are there better models of describing nuclear decay? If so what are they?

2. Jan 3, 2007

mathman

The basic law is quite accurate. The physical assumption is that the probability of an atom decaying is independent of another atom decaying.

3. Jan 4, 2007

pivoxa15

So this law is like the inverse square gravitational and electrostatic laws in that they are very simple but extremely accurate and only when one goes down to several decimal points does it break down?

4. Jan 4, 2007

CarlB

In practice, in most situations, it works very well. However, not always. The problem is that quantum mechanics is a quadratic theory, while radioactive decay follows a linear relation. Consequently, things only decay following the exponential law for times that are not too short and not too long.

Here's some slides showing the issue:
http://www.drake.edu/artsci/physics/petridis_other_files/dnp_talk_10_19_01.ppt [Broken]

Here are some references:
http://arxiv.org/abs/quant-ph/0202105
http://www.aip.org/pnu/1997/split/pnu327-2.htm [Broken]
http://arxiv.org/abs/physics/0505042
http://arxiv.org/abs/quant-ph/0411145
http://arxiv.org/abs/quant-ph/9806079

From the peer-reviewed literature:
http://prola.aps.org/abstract/PRA/v63/i6/e062110

There are tons of articles on this. Search for "Zeno" or "non exponential decay".

Carl

Last edited by a moderator: May 2, 2017