DParlevliet

Indeed, the discrete increment is a particle property. But "any point" is not discrete, but a continuum, caused by a wave property. Without wave properties "any point" is only the center of the detector.

What do you mean with change? For instance a single photon is detected outside the center of the detector. This output cannot be expalined by only particle or only wave. One has to use both particle and wave properties/formula, at the same time.

Indeed, when you measure more photons, then the detector amplitude is determined both by number of particles and wave. So you measure both particle and wave properties. The amplituide outside the detecter center is caused by wave properties.

I don't mean the detector signal output magnitude, but the amplitude of the wave. This amplitiude is determined by wave formula.

The magnitude, which determines the possibility of absorption at that position.

Let us remove the slit in front of the detector. I used it against an argument, but it now confuses. So a single slit and a detector. If a photon is detected, then the detector measures at the same time a particle property and a wave property. So it seems to be possible to measure some wave/particle properties at the same time .

Thanks, that was what I was looking for. But that makes it vulnerable to interpreting language or (even worse) philosophy or science-religion. In science one must use an exact formula or description. It must be described more precise what excludes what and when. With a single slit a detector measures in the pulse the particle energy and at the same time in the detection position the wave amplitude, so both a particle and a wave property. The "which path" is not an accurate description. As above with one slit I think the path is known, but you don't. But with a double slit with "marked" photons it is told that the path is known, but according your view the path is unknown between slits and detector. So "which path" depends on interpreting language, which is not science.

Perhaps I understand. My first confusion was that it is sometimes stated that a photon is a particle or wave but not both at the same time. But a photon always has both particle and wave properties, but they cannot be measured at the same time. According your explanation between slit and detector you don't know exactly the position, so there can be wave effect. Then the detector measures the effect of both particle and wave between slit and detector? What is the cause of this. Is it the fact that a wave and particle classical cannot be combined or can diffraction be calculated with Heisenberg uncertainty?

But isn't diffraction a wave effect?

Indeed, but a spatial detector shows at the same time particle effects (the absorbed photon as a single pulse) and wave effects (the place where it is absorbed). Also with a double slit a detector shows both the single photons as the interference pattern. With a single slit that is the same, only the inteference looks different (diffraction is also an interference effect). But there is diffraction between the first and second slit.

Yes, but terminology must be exactly defined. Diffraction is also an interference effect. So if one state that measurements show that knowing through which slit the particle goes does disappear a certain interference effect, then that is right. But if one claims that this is caused by a fundamental principle of complementary, so acts general also outside the double slit, one must define "which path" and "interference" more accurate

Yes, in front of the detector. The first slit also degreases the signal. If you say that you know the path of a photon going through the first slit ( but you don't detect and thus don't know the path of photons that don't pass through the first slit) then it's the same with the second slit. So how does one define exactly "knowing which path"

And when I place a second slit just above the detector. Then, just as with the first slit, I know in advance which path it will take. Still it will have (wave) diffraction at the first slit.

In Wikipedia "Double slit" the principle of complementarily is defined as "that photons can behave as either particles or waves, but not both at the same time", stating that an interference pattern disappears when the path of the particle is known. But with a single slit you know the path and still the photon diffracts, which is a wave effect. So how is complementarity exactly defined in this case ?

But don't call it time travel, that confuses.

And that is how a lay man debates and read posts.

Every authoritative book tells that a photon has parts of both.

The measurement discussed (post #32) is principally the same as the double slit (post #20). Both are a "double path" measurement, which is the base of an interference pattern. You let a bad counter go over into a bad detector, but that are technical items. There are fast clocks and small pixels so can you prove with practical values that there is no area between the extremes you describe which shows both time and interference? The math I leave to others to comment, but I suppose this only involves the Planck level world. Double slits are much larger then that.

It is a part of physics, but we don't know why. According Brian Greene it is not yet decided if time is continuous or quantized. But at Planck lengths all is so chaotic, that the meaning of before and after becomes meaningless. Anyway I don't think it does influence "change" if time is seen as infinite small (when continuous) or in steps

That is because photons has both particle and wave properties. The particle goes one path, but the wave goes both paths and the wave determines the propability of detection of the particle, even with a single photon. That is because you look to it as classical particles, while a photon has particle (and wave) properties Reflection is not absorption/emission, but reflection on electrons, without making the photon non-coherent. Look to cystal diffraction, based on reflection and interference. Mirrors give interference pattern, like http://en.wikipedia.org/wiki/Lloyd%27s_mirror Read Feynman and you see mirrors and interference. The above measurement is an interference example I used from Brain Green's "The fabric of the cosmos" That is on much smaller (Planck) scales then the above measurement.

I think that wikipedia is not saying that time is quantized, but that you can only measure it quantized.

In that way you know which path the Photon took and that it acted as a particle (which does not mean it is a classical particle). That was the discussion with Delbert about. Now, according the rules of Feynman, will there be interference at detector 2?

Theoretic, but with above experiment where I ask the time, not interference or polarization. So like sb635 argued. Do you agree with him? Or more exact: you will find 3.3 ns (1 m path) or 33 ns (10 m path). Inaccuray of the time measurement is much smaller. Agree?

It is a proposed measurement. I have not done it nor seen elsewhere.

Still my question remains open: if you measure the time between detector 1 and 2 (paths are 1 m and 10 m), what is the result? I am not talking (yet) about interference pattern, only if you know which path the photon took.