sci.physics.electromag

On Wed, 19 Mar 2008, Szczepan Bialek wrote:

> "Timo Nieminen" wrote:
>> On Sun, 16 Mar 2008, Szczepan Bialek wrote:
>>
>>> Now we are able to emit aritifical continous radiation. Such are also in
>>> packets?
>>
>> If we choose. For example, emit a pulse.
>
> We know how long is pulse artifically emitted. Above I have suggested how to
> measure the lenght of the light pulse emitted by hot body.

That would tell us the (temporal) coherence of the source. Experiments
showing that atomic absorption and subsequent re-emission of photons, the
transition from one electronic energy state to another, occurs in a much
shorter time than the coherence time of the source were done more than
twenty years ago.

The goal was to try to measure how long the absorption or emission of
photons took. All they could say was that it took less time than they
could measure. At least some of the experiments looked at transitions with
narrow frequency spectra, implying wavefunctions _much_ longer than the
emission/absorption times.

There were multiple experiments, from the early or mid 1980s or so. Most
of the papers I read were from Phys Rev [X]. "Quantum jump" might have
appeared in some titles if you want to search.

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html