Originally posted by sirnex
Go read from the SCIENCE itself, *not* from sensationalized BS.
Calling something sensationalized BS doesn't refute the experimental results...
These situations are principally derived from the phenomenon known as "delayed choice," proposed by John Wheeler, see Quantum Theory and
Measurement, J.A. Wheeler and W.H. Zurek, eds. Princeton Univ. Press (1983). The QM predictions have been experimentally realized and verified by,
e.g., V. Jacques, et al., "Experimental realization of Wheeler's gedankenexperiment," Science 315 966 (2007), e-print at
; A.G. Zajonc et al., Nature, 353, 507 (1991); P.G. Kwiat et al., Phys. Rev. A 49, 61 (1994); T.J. Herzog et
al., Phys. Rev. Lett., 75, 3034 (1995); T.B. Pittman et al., Phys. Rev. Lett., 77, 1917 (1996). The Jacques experiment is described in Physics World,
"Photons denied a glimpse at their observer" (Feb. 15, 2007), physicsworld.com...
At least one quantum eraser double slit experiment has been accomplished with electrons. I. Neder, et al., "Entanglement, Dephasing, and Phase
Recovery via Cross-Correlation Measurements of Electrons," Phys. Rev. Lett. 98, 036803 (2007-Jan-19), e-print at
This is said to be the electron equivalent of "ghost interference" as reported by D.
Strekalov, et al., "Observation of two-photon 'ghost' interference and diffraction," Phys. Rev. Lett. 74, 3600 (1995), which is nicely described
in P. Chingangbam, et al., "Two particle ghost interference demystified," e-print at arxiv.org...
also Qureshi T., et al., "Quantum Eraser Using Spin-1/2 Particles" (2005), e-print at arxiv.org...
The experimental realizations of delayed choice of which I am aware have all been accomplished with photons. This is mainly due to the ingenious
scheme developed by Marlan O. Scully which employs entangled pairs of photons to accomplish which-path measurement 1) with no interaction; and 2) with
the ability to manipulate the which-path information. M.O. Scully and K. Drühl, Phys. Rev. A 25, 2208 (1982). For pedagogical purposes, I have
continued to use electrons as the quantum units under discussion. With recent successes in achieving entanglement among atoms, it seems likely that
these experiments may be repeated in the near future with various quantum units of matter (if this has not already been achieved). QM being what it
is, there is no question but that the results will be consistent with those obtained with photons.
Summary of the basic idea of delayed choice experiments is available at
For an elegant delayed choice experiment, see Yoon-Ho Kim, et al., "A Delayed Choice Quantum Eraser", Phys.Rev.Lett. 84 (2000) 1-5
Commentary on this experiment is available at
Another excellent experiment is reported at G. Scarcelli, Y. Zhou and Y. Shih (Dep't of Physics, Univ. of Maryland). "Random Delayed-Choice Quantum
Eraser via Two-Photon Imaging." (Dec. 22, 2005) arxiv.org...
Recently, a group advised by Alain Aspect reported a successful delayed-choice experiment with single photons and direct intervention by the
experimenter. V. Jacques, et al., Experimental realization of Wheeler's delayed-choice GedankenExperiment (Oct. 31, 2006), e-print
Paul Kwiat and Rachel Hillmer describe "A Do-It-Yourself Quantum Eraser" in the May 2007 edition of Scientific American . All you need is a laser
pointer and some polarizing filters, and they even tell you where to get the polarizing filters. If I were still in high school, this would be my