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Posted on 07/20/2011 7:59:33 AM PDT by decimon
A violation of one of the oldest empirical laws of physics has been observed by scientists at the University of Bristol. Their experiments on purple bronze, a metal with unique one-dimensional electronic properties, indicate that it breaks the Wiedemann-Franz Law. This historic discovery is described in a paper published today in Nature Communications. In 1853, two German physicists, Gustav Wiedemann and Rudolf Franz, studied the thermal conductivity (a measure of a system’s ability to transfer heat) of a number of elemental metals and found that the ratio of the thermal to electrical conductivities was approximately the same for different metals at the same temperature.
The origin of this empirical observation did not become clear however until the discovery of the electron and the advent of quantum physics in the early twentieth century. Electrons have a spin and a charge. When they move through a metal they cause an electrical current because of the moving charge. In addition, the moving electrons also carry heat through the metal but now it is via both the charge and the spin. So a moving electron must carry both heat and charge: that is why the ratio does not vary from metal to metal.
For the past 150-plus years, the Wiedemann-Franz law has proved to be remarkably robust, the ratio varying at most by around 50 per cent amongst the thousands of metallic systems studied.
(Excerpt) Read more at bris.ac.uk ...
This is why Al Gore and the other global warming hoaxers are not true users of the scientific method. Science is never settled and is always open to new investigation to prove or disprove hypotheses.
What’s next? Ice-Nine?
purple bronze = Li 0.9 Mo6 O 17
The paper: http://www.nature.com/ncomms/journal/v2/n7/full/ncomms1406.html
I would say it was discovered 15 years ago by Kane and Fisher and finally verified experimentally by this group. Not to take anything away from their achievement.
It’s effectively a one dimensional heat sink (and it works better at lower temperatures).
I guess a composite material with trillions of such doped 1D chains ‘baked in’ would act as an effective sink. However: dispersal of waste heat from electronics does seem a better fit than bulk heat transfer from engines.
And when he says it applies... and only how he says it does....and, by definition, it never violates the laws of physics, even if it actually does.....
Thanks. I did a search on ‘purple bronze’ and came up blank.
It would seem that there is no bronze in purple bronze.
ML/NJ
Interesting.
We have plenty of other laws with caveats, they don’t work in this or that situation.
alchemy...
“A natural law or physical law is a description of observed regularities of behavior. It’s not necessarily the case that it will apply in all situations. And it’s certainly not true that there are “laws” that physical systems must obey. “
So true, but when we use the shorthand word “law” most people think of it as a settled, unchangeable thing.
Oh no... what’s that poor girl getting into now?....
purple bronze, a metal with unique one-dimensional electronic properties, indicate that it breaks the Wiedemann-Franz LawDanged nanny-physics laws, anyway.
.... the Wiedemann-Franz law has proved to be remarkably robust, the ratio varying at most by around 50 per cent amongst the thousands of metallic systems studied.Close enough for government work.
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