bhobba said:That isn't quite what they did.
It relied on something called weak measurements:
http://www.tcm.phy.cam.ac.uk/~mdt26/talks/towler_weak_measurements.pdf
Thanks
Bill
Tollendal said:Dear athosanian,
That's in somewhat loose wording was Dr. Aephrain Steinberg (University of Toronto - Canada) has done. More rigorously, you can read it in "Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer" - Science 3 June 2011: Vol. 332 no. 6034 pp. 1170-1173 DOI: 10.1126/science.1202218
The abstract was:
"A consequence of the quantum mechanical uncertainty principle is that one may not discuss the path or “trajectory” that a quantum particle takes, because any measurement of position irrevocably disturbs the momentum, and vice versa. Using weak measurements, however, it is possible to operationally define a set of trajectories for an ensemble of quantum particles. We sent single photons emitted by a quantum dot through a double-slit interferometer and reconstructed these trajectories by performing a weak measurement of the photon momentum, postselected according to the result of a strong measurement of photon position in a series of planes. The results provide an observationally grounded description of the propagation of subensembles of quantum particles in a two-slit interferometer.
Read more at: http://phys.org/news/2011-06-quantum-physics-photons-two-slit-interferometer.html#jCp
Thanks a lot, Tollendal, you are really very helpful !Tollendal said:Dear athosanian,
That's in somewhat loose wording was Dr. Aephrain Steinberg (University of Toronto - Canada) has done. More rigorously, you can read it in "Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer" - Science 3 June 2011: Vol. 332 no. 6034 pp. 1170-1173 DOI: 10.1126/science.1202218
The abstract was:
"A consequence of the quantum mechanical uncertainty principle is that one may not discuss the path or “trajectory” that a quantum particle takes, because any measurement of position irrevocably disturbs the momentum, and vice versa. Using weak measurements, however, it is possible to operationally define a set of trajectories for an ensemble of quantum particles. We sent single photons emitted by a quantum dot through a double-slit interferometer and reconstructed these trajectories by performing a weak measurement of the photon momentum, postselected according to the result of a strong measurement of photon position in a series of planes. The results provide an observationally grounded description of the propagation of subensembles of quantum particles in a two-slit interferometer.
Read more at: http://phys.org/news/2011-06-quantum-physics-photons-two-slit-interferometer.html#jCp
Truecrimson said:Here are some old threads that discussed this experiment.
https://www.physicsforums.com/threads/what-are-the-implications-of-this-experiment.503861/
https://www.physicsforums.com/threa...e-slit-provide-which-path-information.506396/
Zafa Pi said:What am I supposed to make of this:
http://physicsworld.com/cws/article/news/2014/oct/09/are-weak-values-quantum-after-all
Well that's not very helpful. The article I linked to in post #9 says the trajectory (which slit) of no single photon was observe. But several other articles claim otherwise, e.g. http://phys.org/news/2011-06-quantum-physics-photons-two-slit-interferometer.html#jCp. I listened to Steinberg for over an hour and though he intimated he could observe which slit and still retain interference (I don't believe it) there was a lot of vagueness with regards to weak measurements. I've tried plowing through the technical details, but it's very unpleasant and I lose the forest for the trees. Here (https://www.perimeterinstitute.ca/news/are-weak-values-quantum-dont-bet-it) Combes seems skeptical about the whole enterprise.bhobba said:Its just semantics.
What weak measurements are is well known. Calling them quantum or not isn't of any value.
Thanks
Bill
Zafa Pi said:I'm convinced of your knowledge and insight, but am I too dense for you to pass on some enlightenment and clear the fog?
The two-slits experiment is a classic experiment in quantum mechanics that demonstrates the wave-particle duality of light and matter. It involves shining a beam of particles, such as electrons or photons, through two parallel slits and observing the resulting interference pattern on a screen.
The two-slits experiment proves that particles, such as electrons or photons, can behave like waves and exhibit interference patterns. This contradicts the classical Newtonian idea that particles always behave like solid objects.
In the two-slits experiment, a beam of particles is sent through two parallel slits and allowed to hit a screen on the other side. The particles can pass through both slits simultaneously and interfere with each other, creating an interference pattern on the screen. This pattern is only observed when the particles are treated as waves.
The two-slits experiment is significant because it demonstrates the fundamental principles of quantum mechanics, such as wave-particle duality and superposition. It also challenges our understanding of the physical world and has led to further research and advancements in quantum physics.
Yes, the principles demonstrated in the two-slits experiment have been applied in various technologies, such as electron microscopes and diffraction gratings. It also has implications in fields such as cryptography and quantum computing. However, the experiment itself is a simplified model and may not fully reflect the complexities of the real world.