[tt] the physics arXiv blog

[Eugen Leitl]

----- Forwarded message from the physics arXiv blog <howdy at arxivblog.com> -----

From: the physics arXiv blog <howdy at arxivblog.com>
Date: Wed, 18 Jun 2008 13:58:02 -0500 (CDT)
To: eugen at leitl.org
Subject: the physics arXiv blog
Reply-To: the physics arXiv blog <howdy at arxivblog.com>


[1]the physics arXiv blog

   [2]The embarrassing lightness of photons

   Posted: 18 Jun 2008 12:08 AM CDT

   [3]Photon force 

   Here's a conundrum for you. What is the momentum of light in a
   transparent dielectric medium?

   If the answer doesn't trip off your tongue, that might be because
   nobody else knows either. Amazingly, there are two lines of thought:
   In 1908, the German mathematician Hermann Minkowski guessed that the
   momentum was equal to nE/c (where n is the refractive index, and E and
   c are the energy and speed of light in a vacuum).

   A year later,  his contemporary Max Abraham suggested that the
   momentum is equal to E/nc.

   A century since then and we're none the wiser. An embarrassing state
   of affairs for theoretical physics, wouldn't you agree?

   Today Weilong She and pals from Sun Yat-Sen University in Guangzhou,
   China, announce that they have the answer. And they got it by
   measuring the recoil on the end face of a nanometre-sized fibre
   exerted by outgoing light. (This isn't the well known pressure caused
   by specular reflection but something  a little more subtle.)

   The experiment is impressive because it is designed in such a way that
   if Minkowski were correct the fibre should be pushed in one direction
   and in the other if Abraham were correct.

   So the result is the first to unambiguously favour one theorist over
   the other.

   And the winner is...drum roll...Abraham.

   It's about time.
   Ref:  [4]arxiv.org/abs/0806.2442: Observation of a Push Force on the
   End Face of a nm Fiber Taper Exerted by Outgoing Light

   [5][arXivblog?i=JSxcGb] 
   [6][arXivblog?i=XjBgFI] [7][arXivblog?i=V8f5II]
   [8][arXivblog?i=axp8ci] [9][arXivblog?i=gMgcbI]
   [10][arXivblog?i=jjHeai] [11][arXivblog?i=w0LUeI]
   [12][arXivblog?i=iNQpwi] [13][arXivblog?i=46vcnI] 
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References

   1. http://arxivblog.com/
   2. http://feeds.feedburner.com/~r/arXivblog/~3/314347846/
   3. http://arxivblog.com/wp-content/uploads/2008/06/photon-force.jpg
   4. http://arxiv.org/abs/0806.2442
   5. http://feeds.feedburner.com/~a/arXivblog?a=JSxcGb
   6. http://feeds.feedburner.com/~f/arXivblog?a=XjBgFI
   7. http://feeds.feedburner.com/~f/arXivblog?a=V8f5II
   8. http://feeds.feedburner.com/~f/arXivblog?a=axp8ci
   9. http://feeds.feedburner.com/~f/arXivblog?a=gMgcbI
  10. http://feeds.feedburner.com/~f/arXivblog?a=jjHeai
  11. http://feeds.feedburner.com/~f/arXivblog?a=w0LUeI
  12. http://feeds.feedburner.com/~f/arXivblog?a=iNQpwi
  13. http://feeds.feedburner.com/~f/arXivblog?a=46vcnI
  14. http://arxivblog.com/
  15. http://www.feedburner.com/fb/a/emailunsub?id=8632699&key=kesJ612ZsV
  16. http://feeds.feedburner.com/arXivblog
  17. http://feeds.feedburner.com/arXivblog

----- End forwarded message -----
-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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