Category Archives: diffraction

Time Zero – A real Place?

“Time Zero – Ctime”

I would like to discuss a few other things about photons and also very high speed particles and their implications for a special point in time.  Some of these are just thought experiments and may have no basis for a new theory, but some of you may find it interesting at least and perhaps there is some promise of truth in them.

Since the photon experiences zero time during flight, it would be nice to know what is actually going on within the photon during the possibly billions of years of its flight. We know that near the speed of light, time slows dramatically and that a spacewoman in a space ship at near light speed would experience time as if it passes normally, but a stationary observer would see things quite differently. A clock on the wall continues to tick off regular seconds to her while her brother on earth gets older at a much faster rate, all the while knowing that her clock is going very slowly and she is staying young as he grows old.

But a photon is going much faster than a space ship ever can. The entire time of flight is reduced to zero so nothing can happen within the photon during flight.  The flight ends as soon as it begins for the photon. Yet we know there is a finite flight time from our observer perspective, sometimes billions of years for flight, as we see the same photon.

An interesting point is that the photon is capable of living forever because it cannot age if time is stopped, and in cloud chamber experiments we can measure the lifetime of some collision reactions only because the time of reaction is slowed for a high-speed particle due to time dilation. Time dilation near or at c is a real thing.

Yet we know that there is a finite and measurable time of flight from there to here from our perspective, and that a photon, if it has a frequency associated with it should vibrate hundreds of times during each foot of travel.  That is, if we believe it is still vibrating and not frozen as well. When it lands we know that its frequency is related to its energy and thus its color.  Does the photon actually experience this vibration, or does it all occur only when it starts and again when it encounters an obstacle that slows it down (such as within a crystal, or passage through water), or when it changes direction such as during a bounce off of a mirror… or does it occur again only at the moment of destruction, or as it melds around a small object?

We know that the emission of a photon is related to the change in energy states of an electron and both the energy and the frequency of the photon are related to that change of state. So the frequency is a physical attribute of the photon. We aren’t certain what exactly is going on since there are the contradictory facts that the clock of a photon does not change during flight, yet significant time elapses externally, and a photon has vibrational modes.  We also know that the phase doesn’t change, so the implication there is that no vibration actually takes place.  Is something else going on?

Ctime

Here is a new thought. If the time experienced by a photon is zero, where is the photon during the time of its flight? Is there such a time (physicists call it null time) and is it possibly a real place, a relativistic time zero?  Let me call it “ctime” for simplicity, time at speed c.  Ctime would then be where the photon is during flight, a place where time is stopped. Nothing happens, nothing moves, at least not within the photon. The photon moves through space, and doesn’t even vibrate, but the photon experiences nothing because it is embedded in ctime.

Now, suppose all ctimes are the same!  A special point located in relativistic time.    Not the same space-time, but the same time-space, a special place where time is stopped due to relativity, all connected by the null paths.  Photons that have paths that don’t cross would still be in the same place in time – ctime – throughout their flight, but would not ever occupy the same space.  

Photons that have paths that do cross would occupy the same space and same time at the crossing point even if they crossed several decades apart because both would be in ctime and both pass through the same space at some point. The physical times we calculate at the crossing (different) would not be the same as the ctime the photons would experience (same).  Ctime would exist for the photon throughout its existence and even afterward, at least until the null path was disturbed by another photon crossing the same null path.    I say that because the time is frozen and doesn’t change and therefore any point in the null path that is not disturbed remains undisturbed even if the last point of that path is a screen or detector or a piece of rock or someone’s eye.  How can the previous points know if time does not change for those points all stuck in ctime?

Would such photons interfere with each other? In other words, is it possible for a photon that passes through a slit today to actually interfere with another photon that comes through tomorrow?  They would both pass through the same space at the same time in timespace – ctime.  I think it is theoretically possible and thus becomes an alternate way to explain some quantum weirdness effects.  Certainly, it seems more possible than multiple universes.  When does the ctime collapse for a photon? If it is a real place in time, does it even know that the photon has ceased to exist?  For interference to occur in a slit due to ctime, it must continue to exist until at least something physical cuts through the spacetime of the path, such as the placement of a detector or the disturbance of another photon trying to occupy the same space and ctime.  Even then if the detector is removed before the second photon comes through, ctime (at the photon crossing point) is undisturbed unless the detector happens to disturb the point that the photon paths cross, normally some point well past the detector placement.

Let’s go over that again, slowly.  A photon is emitted.  It immediately stops all internal activity and is, in effect in suspended animation until it hits something.  For the photon, the distance of the flight path is shortened to zero and time stops.   Space and time are severely warped.  For the photon, the entire trip from a far galaxy is reduced to zero time and zero distance.  Both space and time are reduced to dots.   Space and time are warped that much.

We can conceive of space being zero distance, a dot, and create a very simple drawing with both ends of the path conjoined at a dot on the paper.  But what about time?   If time is reduced to a dot, where is it?   What I’m suggesting is that the time dot is the same place in time for all photons.  That place in time is what I’m calling ctime.    However, the time-space dot occupies the entire length of the flight path and continues to exist there until each point is later disturbed.   A null path consisting of a continuous line of space-ctime, like a deep valley in time that the photon passes through, warped by its speed.  The valley hangs around in time (ctime) even after the particle ceases to exist at every point in space, because time does not change there.

If the paths of two photons cross, but at different times as we measure it,  then the two photons exist in the same space, but not the same time (as we measure it) – different space-times.  Except… it is my suggestion that they do exist at the same time (for the photons) at the same space-ctime, and never come out of it until that particular space at the crossing point is disturbed.   It would be an alternate explanation for the interference of photons that are emitted one at a time over a period of days or weeks.  

The first photon through a given slot occupies a particular space and is also hung up in ctime.   Its presence in ctime for that space exists even after the photon hits the target.   Each point in the path of the photon experiences the photon in passing as a warp in time.  No information is possible for the past or the future of the photon – and so each point is left with a warped time that is frozen there in ctime.   When another photon happens to cross that same space later, the ctimes are also crossed at that same point and thus the newer photon is shaken by the occurrence just as if it had brushed up against the earlier one.   Interference!   If a slot is closed, then the previous photon ctime paths are disturbed by the closing and no interference occurs when a newer photon comes along later. 

This has implications for high-speed particles with mass as well.  As they approach relativistic speeds, there is time and space distortion for these particles as well.  Electrons and even much heavier particles show diffraction patterns and also show interference patterns even when fired one at a time.  In their cases, the valley of ctime would not be as deep and possibly not persist as long, but space and time are warped just the same.  The interference of one particle with another at a later time may be just the same effect - an existence of a ctime in a not-quite null path left by one particle that disturbs one coming along later.  

An experiment might be constructed such that a paddle sweeps through the entire area where photon interference might occur.  The sweeps to occur between each photon emission.  Such an experiment  might prove this theory if the result is no interference pattern buildup over time when the paddle is used but interference does occur when the paddle is not in use.  I’m suggesting a simple paddle that is wide enough to span the multiple interference points and placed normal to the screen, a paddle that mechanically sweeps through and disturbs the ctimes so that no photon crosses another’s undisturbed ctime.  A paddle next to the slits will not do the trick, so I doubt that this experiment has been done before.  A paddle that only sweeps some of the crossing points would in effect blank out some of the interference pattern and not others.   A real test.

Copyright 2007 by James A. Tabb

Marietta, Ga. 
 

Double Slit Weirdness

Double Slit Weirdness

Single Slit ExperimentWhen a proper light source (coherent – light from a single source all at the same frequency) is placed in front of a screen with a narrow slit, the light is diffracted (spread out) as it goes through the slit and appears as a shaded band centered on a screen or photographic film.  The light is scattered by the edges of the slit as shown in the first figure.

Single Slit Diffraction. 

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Double Slit Setup

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Double Slit Setup

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Double Slit InterferenceIf we add two more slits located side by side between the first slit and the screen, the light passing through each of the new slits is diffracted again such that the photons from each slit are bent across each path and combine to reinforce or cancel each other where they strike the screen.    The result is an interference pattern (light and dark bands) on the screen. 

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If you block either of the two middle slits, the interference pattern disappears.  The diffracted light from the forward slit is diffracted again by the open slit in the second screen, but no interference pattern emerges because the other slit is blocked.

It can be shown that when both slits are open, the interference pattern seen can be duplicated by drawing the photon as a wave at the frequency of the source at each of the second screen slits and then combining the resulting waves by addition and subtraction of the waves where they mix behind the slits.  This addition and subtraction of the waves into the interference pattern seems to prove that the light is a wave.   Indeed, if the light is a particle, it would imply that their interaction cancels particles in the dark areas or at the very least, they bump each other into specific areas on the screen.   We know that does not happen. 

However, if you replace the screen by a photographic film and reduce the intensity so that only a few hundred photons are sent through before the film is developed, you will find that you can see the individual places the photons hit as dots on the screen.  You can also see that the individual dots are organized so that they fall into the bands of the interference pattern and duplicate it.  Keep the film in place long enough and the patterns become more complete.  Put a cover over one of the slits before you start and you will find that the film still shows dots, but no interference pattern, only the diffraction band. 

The dots seem to prove that the light is indeed a particle, not a wave, but yet they seem to interfere with each other like a wave when both slits are open.   A mystery, but not necessarily weird.

Quantum Weirdness at Work

Now if the light source is reduced in intensity enough to send only one photon at a time, a weird result can be seen if the photographic film is left long enough (days or even months in a very dark box) where both slits are left open.  The interference pattern continues to develop on the film, even though there is no possibility of interference (or even photon bumping) unless the individual photons go through both slits somehow. 

A test for this is to remove the film and put a detector behind the slits.  But then we find that the detectors only detect one photon at a time and only through one slit or the other, never both.   The interference pattern never develops if either slit is covered.  Quantum Weirdness at work.

There have been some very inventive tests such as using super-fast mirrors behind the double slits that switch in and out of the path between the time the photon leaves the slit and before it arrives at the screen.  The results are the same.   When either slit is covered, the interference pattern disappears but when both are open it reappears, even if the photons arrive only one at a time.

Since the photographic plates seem to prove that the light is a photon and never goes through both slits, the quantum weirdness problem arises and part of the current explanation is that the measurement (putting a detector in the path) always disturbs the measurement.  In fact a whole class of quantum theory has developed around the inability to make precise measurements due to the measurement disturbance problem.

Quantum Electrodynamics (QED) explains this behavior using simple diagrams to show the probabilities of where the photons will land.  It cannot predict where any one photon will land, but given enough photons, it can predict the pattern very accurately.   QED does little to explain the weirdness of it all.

I have a simple theory on how all this works that I will get to eventually.  Next I want to talk about Polarized Light Weirdness.