Hi Harry,
I've been lightly following the Afshar experiment for some time at WikiPedia.
The article -->
http://en.wikipedia.org/wiki/Afshar_experiment
and the discussion -->
http://en.wikipedia.org/wiki/Talk:Afshar_experiment
Has there been a recent change in this debate? Last I checked the debate was
still in full swing if BPC (Bohr's Principle of Complementarity) was violated.
I also had a proposed double slit experiment. The double slit normally detects a
photon or electron strike. We could take this one step further by detecting the
direction of impact. For example, we know that if an electron collides in a bulk
of metal there's an electric wave that propagates away from the collision
location. Furthermore we can detect the direction of impact by analyzing such
electric wave collision patterns. I see three possibilities -->
1. Electron came from left slit.
2. Electron came from right slit.
3. Electron came from the middle of both slits.
It's possible option #3 would occur every time. Another possibility is for
option #1 or #2 to occur while still maintaining the interference patterns.
Regards,
Paul Lowrance
Harry Veeder wrote:
> More detail in this pdf file:
> http://arxiv.org/pdf/quant-ph/0702188
> Harry
> ------------
>
> http://www.physorg.com/news92937814.html
>
> Physicists Modify Double-Slit Experiment to Confirm Einstein's Belief
>
> Work completed by physics professors at Rowan University shows that light is
> made of particles and waves, a finding that refutes a common belief held for
> about 80 years.
>
>
> Shahriar S. Afshar, the visiting professor who is currently at Boston's
> Institute for Radiation-Induced Mass Studies (IRIMS), led a team, including
> Rowan physics professors Drs. Eduardo Flores and Ernst Knoesel and student
> Keith McDonald, that proved Afshar¹s original claims, which were based on a
> series of experiments he had conducted several years ago.
>
> An article on the work titled "Paradox in Wave-Particle Duality" recently
> published in Foundations of Physics, a prestigious, refereed academic
> journal, supports Albert Einstein¹s long-debated belief that quantum physics
> is incomplete. For eight decades the scientific community generally had
> supported Niels Bohr¹s ideas commonly known as the Copenhagen Interpretation
> of Quantum Mechanics. In 1927, in his ³Principle of Complementarity,² he
> asserted that in any experiment light shows only one aspect at a time,
> either it behaves as a wave or as a particle. Einstein was deeply troubled
> by that principle, since he could not accept that any external measurement
> would prevent light to reveal its full dual nature, according to Afshar. The
> fundamental problem, however, seemed to be that one has to destroy the
> photon in order to measure either aspects of it. Then, once destroyed, there
> is no light left to measure the other aspect.
>
> ³About 150 years ago, light was thought to behave solely as a wave similar
> to sound and water waves. In 1905, Einstein observed that light might also
> act as being made out of small particles. Since then physicists found it
> difficult understanding the full nature of light since in some situations it
> acts like a particle and in others like a wave,² Flores said. ³This dual
> nature of light led to the insight that all fundamental physical objects
> include a wave and a particle aspect, even electrons, protons and students.²
>
> Afshar conducted his initial theoretical and experimental work at IRIMS,
> where he served the privately funded organization as a principal
> investigator. He later continued his work at the Harvard University Physics
> Department as a research scholar, where he was able to verify his initial
> findings before going to Rowan.
>
> In 2004, Afshar claimed that he had devised an experiment that challenged
> Bohr¹s principle of complementarity. The Rowan team was formed to verify
> Afshar¹s claim at extremely low light intensity levels. Afshar, Flores and
> Knoesel conducted experiments at Rowan that validated Afshar¹s initial
> findings for single photons.
>
> In this modified double-slit experiment, a laser beam hits a screen with two
> small pinholes. As a particle, light goes through one of the pinholes.
> Through a lens system, the light is then imaged onto two detectors, where a
> certain detector measures only the photons, which went through a particular
> pinhole. In this way, Afshar verified the particle nature of light. As a
> wave, light goes through both pinholes and forms a so-called interference
> pattern of bright and dark fringes.
>
> ³Afshar¹s experiment consists of the clever idea of putting small absorbing
> wires at the exact position of the dark interference fringes, where you
> expect no light,² Knoesel said. ³He then observed that the wires do not
> change the total light intensity, so there are really dark fringes at the
> position of the wires. That proves that light also behaves as a wave in the
> same experiment in which it behaves as a particle.²
>
> The findings of the Afshar experiment were published online on January 23 in
> the Foundations of Physics, an international journal devoted to the
> conceptual bases and fundamental theories of modern physics, biophysics and
> cosmology, with several distinguished Nobel laureates on its editorial
> board. The print version was published in the February 2007 edition and is
> now available in libraries throughout the world.
>
> ³The important new contribution is that light carries both wave and particle
> aspects at all times, and future experiments will further clarify the nature
> of each component.² Afshar said.
>
> Flores continued, ³It is interesting to note that even after 80 years we can
> still gain a better understanding about the nature of light using refined
> measurement techniques and creative ideas and therefore are able add to the
> vast insights of former scientists.²
>
> Citation: Paradox in Wave-Particle Duality, Shahriar S. Afshar, Eduardo
> Flores, Keith F. McDonald and Ernst Knoesel, Foundations of Physics, 23
> January 2007, DOI 10.1007/s10701-006-9102-8
>
> Source: Rowan University
>
