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Re: projection operators (e.g. polarizers??)



I don't understand Carl's posting. Energy that doesn't "pass
through" is absorbed by the polarizer. So what's so amusing?
Regards,
` Jack

On Wed, 3 Mar 2004, Brian Whatcott wrote:

I shall of course look over Carl's discussion when I have a moment.
But is there a conceptual difference between this puzzle and the
germanium diode set up to rectify the thermal noise from a hot resistor?

Brian W

At 10:48 AM 3/3/2004, you wrote:
JSD made a very interesting and thoughtful posting about the
unitarity of polarizer operations. I have probably mentioned this
before, but I can't resist bringing it up again:

A Faraday rotator sandwiched between two linear polarizers oriented
at 45 degrees to each other makes what is sometimes called an
"optical diode." That is, it only permits light (of a particular
wavelength) to pass through it in one direction.

So if I put an object A on the "input" side and another object B on
the "output" side, more radiation flows from A to B, right? If so, a
spontaneous temperature difference will exist between them, which I
can use to run a perpetual heat engine!

It's an amusing puzzle. Discussion here:
http://usna.edu/Users/physics/mungan/Scholarship/FaradayIsolators.pdf
--
Carl E. Mungan, Asst. Prof. of Physics 410-293-6680 (O) -3729 (F)
U.S. Naval Academy, Stop 9C, Annapolis, MD 21402-5040
mailto:mungan@usna.edu http://usna.edu/Users/physics/mungan/


Brian Whatcott Altus OK Eureka!


--
"Don't push the river, it flows by itself"
Frederick Perls