# What stochastic process is associated with spontaneous electromagnetic radiation?

Imagine one have an ideal sensor, which can convert the emission to some kinds of signal (typically, voltage, and suppose no noise at all), then what process can describe the measure data? Is it related to Stochastic electrodynamics?

-
I also post my question on Physics Forums, where Fermi's golden rule is mentioned. –  ziyuang May 25 '11 at 7:49
Just looking at the wikipedia page, I can tell that stochastic electrodynamics (SED) has zilch to do with your question. SED is apparantly an attempt to explain ground state energy without quantum mechanics. It also seems to be a controversial approach. –  Raskolnikov Jun 8 '11 at 9:02

## 1 Answer

The usual physics assumption for spontaneous emission of radiation (which I think is what you're talking about here) is that of a Poisson process; that is, if one has a large number of possible emitters, the times between consecutive emissions is not correlated. On the other hand, if we have only a single emitter, then the time at which it emits follows the exponential probability distribution.

These things seem to have nothing to do with Stochastic electrodynamics (but I admit I'd never heard of it and am not inclined to study it).

-
Poisson process describes emission counts (when an emission occurs), but I still want to find an process describing the emission strength (the measured data, as stated in the question). –  ziyuang Jun 8 '11 at 6:11
The measured data is the Poisson process. That is, if your measurement is over the time interval T, then the probability you will get a measurement of X, which is to say that you will measure X photons, is $P(N(T) = X)$ where $N(T)$ is the Poisson process at time T. –  Carl Brannen Jun 9 '11 at 16:44
thank you, I had some misunderstanding about Poisson process. –  ziyuang Jun 11 '11 at 17:15