Friday, September 3, 2010

Quantum Double-Slit NEW Innovative Thought Experiments

By: Valerian Texeira.


Quantum Mechanics (QM) investigates the behaviors of matter basically at its subatomic or the Quantum level (atoms, protons, electrons, photons) at which the matter said to behave in an unpredictable or erratic manner. In other words, what we take for granted that will CERTAINLY HAPPEN in the human relativity (meter) world scale, happens quite differently or “weirdly” in the subatomic particle level explained in the Eisenberg’s “Uncertainty Principle”. It can be practically demonstrated in a famously known Double-Split (DS) experiment. First of all it shows us that matter at its sub-atomic level remains as an omnipotent WAVE when not observed or “not measured” but instantly becomes a PARTICLE when measured or observed! It follows that the subatomic matter can be at two (or more) places at the same time described as quantum Entanglement, Superposition or Non-Location. The most bizarre thing of all (so far) is that our present choice of observation (measurement) profoundly influences or changes its past (Delayed Choice Eraser)! However, we will never know all its outcome or the unpredictable RESULTS until we conduct the specific quantum DS experiments.

However what I found out in here is; if we further make some new simple changes, i.e. add or remove few centimeters in width, length, distance, in the DS apparatus we can get some more or new FLUCTUATING results that may not consistent with the conventional QM results! For example, we may get Two Band pattern instead the INTERFERENCE pattern even when NOT measuring or observing the photons entering the slit or some entirely new kind of pattern will emerge, which has never been recorded before, which at the end may somewhat contradict the conventional QM results. Nevertheless the most important purpose of all the following DS thought experiments are to try to understand the quantum phenomenon such as Delayed Choice Eraser, Entanglement, Superposition or Non-location and more with some simple forms of the DS experiment so it becomes easy for a lay person like me to conceptualize it.

Conventional QM Double-Split Experiment :

Let us first enter into a conventional QM’s DS experiment original set-up. One side of the room a Photon Emitter (PE) after which, at a given distance the experiments main DS apparatus, is a thin metal sheet of one millimeter (m/m) thickness having two slits and the middle gap between the two slits 0.5 m/m. At its back at a given distance an electronic screen device to record the photon hitting. Now when the photon emitter start sending the photon one by one towards the DS then a well known INTERFEARENCE pattern will be formed at the back screen. However if you install a Proton Detector (PD) on the entrance of a slit to see or measure from which slit each of the photon enters, amazingly enough only Two Bands will appear on the back screen. Of course both the results fully in accordance with the conventional QM Uncertainty Principle.

Now what will happen if we make a little change in the middle DS apparatus of this experiment? Perhaps there could be many such new QM experiments that the scientists yet to perform. However here I would like to present some of my laypersons ideas or thought experiments of introducing some new simple changes in the QM’s DS apparatus that could probably bring entirely new kind of variable or fluctuating patterns that has (perhaps) never been imagined before, put forward in the following:

Increasing Gap Between The Double-Slit - The First New Thought Experiment:

In our first new DS experiment let us keep everything in this set-up same except increase the gap between the two slits (in the middle metal sheet apparatus ) from 0.5 m/m to 10 centimeters, which in fact 200 folds more than the old one. Start the PE sending the photons one at a time towards the slits with the detector OFF. After some longer time if we look at the back screen instead of the Interference pattern we will most probably see only Two Bands (adjusting the back screen close enough to the middle DS apparatus it may become still clear) which may seem contrary to the QM prediction. NEVERTHELESS if the photon behaves like wave “when not Observed”, two bands should appear in this first DS experiment! However if you switch ON the photon detector then once again one will get the prominent Two Bands exactly same as the QM do. In other words in this first new quantum DS experiment IRRESPECTIVE of the presence or absence of an Observer (PD) measurement, mostly two bands will be formed at the back screen. This is just the beginning to show how some changes in the quantum DS apparatus can create some fluctuating or erratic results. However this first DS experiment still creates the same conventional QM’s Interference and Two Band patterns if one increase or decrease the vertical width of the slits. Similarly replacing the photon with electron or white, blue red, laser etc lights, beams would not bring in such varying results.

Interestingly however, if we increase the horizontal width of the two slits considerably enough (keep all the rest the same) the resulting Interference pattern (if any) will be quite different from the conventional DS. Finally by increasing the horizontal width of one slit enough while keeping other slit same as before, the resulting pattern may be mostly a single band, like the outcome of a single slit or will it still perform the interference pattern? One cannot be any sure! The only CERTAINTY is when a Observer (PD turned ON) placed on the double slit the result will be always the same old Two Bands on the back screen no matter what the, distance, gap, width (vertical, horizontal) thickness of the DS apparatus.

Increasing The Thickness Of The Double-Slit – The Second Thought Experiment:

In this second experiment once again let us keep everything in the set-up same except increasing the thickness of the DS sheet (middle apparatus) from the one (1) m/m to one meter, which in fact 1000 times more than the original set-up. Start the photon emitter sending photon towards the DS and put ON the PD (observer) to see through which slit each of the photon enters. After some time there will be the prominent two bands on the back screen exactly same as QM’s DS photon particle prediction. Now put OFF the detector and start the emitter. After sometime surprise, surprise! Unlike the QM prediction of Interference patterns, I guess there will be barely any photon hits recorded on the back screen! Because in my opinion, if the photons behaves like waves when not observed (detected), then as the wave enters into the splits while going through its one meter long passage due to its natural process of expanding it will hit both side of the slit-wall and bounce back interfering with itself creating some sort of random ripple effect inside the slit so when the next photon enters into the slit this photons ripples will hinder or block its passage as a result the photons which entered the slit somewhat fail to come out from the other side of the slit as expected.

Now to make the picture more clear let us make the sides walls inside the slit mirror-polished so all the photon waves hitting inside of the slits get reflected back more effectively (high utilization) so the next photon entering that slit get totally stuck so instead of the Interference on the back screen In the other experiment make the side walls of one slit black other highly mirror polished. The result (without detector) may be, in almost all the recorded photon hits on the screen only the half part of the photon hit registered while its other part missing in all the recorded photon hits on the screen. In one word when the Observer not present it would be totally a chaotic or messy scene. Therefore, all these experiments show that the QM claim of getting Two Band pattern in the DS experiment when Observed or measured is absolutely right! However the same claim of getting Interference pattern in the DS experiment when NOT Observed is NOT always right! This may suggest that matter can be confirmed more like a particle than a wave!

Simple New Innovative DS Experiment To Show Quantum Delayed Choice Eraser:

In this experiment let us put two tubes laid parallel and attached to each other in a straight line, like a Double-Slit. However the most important change in this DS experiment is that the one side length of the tube is one Kilometer long ( name it A) but the other side cut short to only one meters long (name it B). A photon emitter on its entrance side where both slit joint opening and two separate electronic screens on its exist side, one after one Kilometer (A) and another after one Meter (B) to record the photons hits. Also two Photon Detectors (PD) placed one at the Joint entrance side and the other at the exit ‘A’ side to see in which the slit (tube) the photon enters or from which side it exit. The PD can be switched ON or OFF as and when required. Now let us start the photon emitter with the PD switched OFF (unobserved). After some time, according to the QM I guess, we most probably see some kind of Interference (wave) like pattern on both the screens A and B. However, a new strange quantum finding perhaps never been thought before may emerge. If the photon as a “wave” enters both the side and needs to get merged at the exit side to become one as the QM prediction then there needs to be some kind of back side photon connection (Wormhole?) from A to B! However it can also logically mean, now we know that the photon(s) hit recorded on the back screen “A” has “certainly” came through the slit “A” and the photon(s) hit recorded on the “B” screen has “certainly” came through the slit “B”. This fundamentally violets the QM Uncertainty Principle therefore only one single band each on both the screens ( total Two Bands) should be recorded even when the PD put OFF! What are the possibilities? Have anyone ever tried this DS experiment before?

Now if we switch ON the PD (or observe) at the entrance side, there we will clearly see one single band on both (A and B) screens (total Two Bands), which confirms the particle position of the QM’s DS experiment when observed. Now put OFF the PD at the entrance side but put ON the PD on the exit (back) side A. Perhaps the result will be the same, one single band each on both (A and B) screens exactly like the PD switched ON while at the entrance side. However there is a basic difference, as we know one side of the tube is only one meter long but the other side one kilometer , so the photon needs to take 1000 times more time to reach this (longer) side of the screen. Now when the second half of the photon (wave) about to come out of this exit side yet to be detected by the PD (observer) at A, the first half of the electron had already hit the short (B) side of the tube screen nearly1000 times earlier in the wave form. However since detecting (observing) the photon wave instantly collapses it into particle, the B side also needs to become a particle. For this to happen 1). This photon wave should have the ability to travel reverse back in time nearly 1000 times and ERASE the photon wave and replace it with a particle when the PD (Observer) switched ON, or 2). The photon wave has the ability somewhat to DELAY hitting the (short side) B screen until its other (longer) part completes its journey to decide whether to remain as a wave or become a particle, OR 3). Each and every photons since its BEGINNING of time knows beforehand whether it will end up detected (measured) by some observers or not thereby able to react accordingly (wave or particle) in the Universe. I think this DS experiment and its explanation , logically or conceptually simple for a lay person like me to understand the QM Delayed Choice Eraser phenomenon.

DS Experiments in Fiber Optic Cable To Show Quantum Entanglement:

One can conduct this DS delayed eraser experiment also in a fiber optic cable so one can conduct it with thousands of kilometers long distance. Place two fiber optic cable facing opposite direction. A photon (or electron) emitter at the middle also a photon splitter and reflectors to split a single photon and send the two half’s on the opposite directions through the cable. One cable can be only one meter long and the other thousands of kilometers (one can keep the cable coiled round to make it easy). At the end of both the cables a electronic or computer screens to record the half photon hits also the a PD to detect photon at the longer end. The Delayed Choice Eraser quantum effect may be more profound in this experiment. However another most important quantum phenomena called Entanglement or Superposition in which the information travelling faster than the velocity of light (Non-Locality) can be shown in the following. Keep both the opposite cables thousands of kilometers and equal length. Now split one photons and send it on the opposite side. As we know the photons to travel at the velocity of light in the opposite direction, then that information or communication between them needs to travel at least twice (or far more) the speed of light for both the split photons to become particle instantaneously when we observe one of them at one end which is known as Non-Locality phenomenon. Once again, in my opinion this DS experiment is logically or conceptually simple for a layperson like me to understand the QM Entanglement or the Non-Location. Also all these DS experiment may suggest that at the quantum level matter can be confirmed more like a particle than a wave!

Quantum OBSERVER What Sense Qualification - Schrödinger’s Cat:

In Quantum DS experiment the observers observation (of the subatomic quantum materials) always shown as the visual sight. Now, the question is what about observing or measuring it by senses other than the visual sight? What about measuring it by sound, smell or touch? Suppose in a quantum DS experiment the photon detector attach to a sound devise so when the photon enters the slit A it makes one kind of sound and another kind of sound if it enters into the slit B. We know according to the QM when the detector switched OFF there will be a Interference pattern at the back of the Screen. However when the detector switched ON, even when the detectors visual recording of the photon entering the slit completely absent (or ERASED before the observer can see it) still the Observer knows whether the photon entered the A or the B slit by the detector sound difference. Does this collapse the photon into particle thus record two bands on the back screen? One can conduct similar experiment with the touch and smell whether they can also act as the measuring observer medium. If it works then one NEED NOT open the Schrödinger’s Box to know the cats condition inside. One will certainly knows the cat is ALIVE and not DEAD as it constantly calls (sound) from inside the box.

There arise many such important questions about what qualifies a person to be an observer. Can a blind person or blindfolded serve as an Observer? Can a mentally challenged, retard or a small baby qualify as an observer? Can the animals, pets, higher primates qualify as the Observers? Suppose a dog or a chimp trained to look at the photon detector attached with light or sound so if the photon enters the A slit one color of light or sound emitted or if it enters the B another color or sound emitted , so the animals sees or hears two different colors or sounds when the photon enters the two different slits. Does this makes or qualifies the animals as Observers thus collapsing the wave function or the photon turning into particles, two bands on the back screen? Let us go one step further suppose the animals are trained to show (by some sign) to the experimenter, which color of light it saw or the sound it heard, when and how many times , would it collapse the wave function of the photon? If it turns out to be true then does it prove that the animals possesses the self consciousness, which the quantum spiritualist not so keen to discuss about?

Finally, I have many QM questions, for ex: if you switch ON a bulb inside a closed room ( accidently, not knowing it) from outside, according to QM there will be NO light shining inside as long as NO Observer to see inside and collapse the electro magnetic light wave into the particle! What about doing it with the proton emitter in a closed room sending photon on the screen while no one observing? Will there be any record of the photon particle left on the screen? Is this a silly nonsense question? I am a lay person and I have many such QM questions for which I seek answers and I would be very grateful if anyone provides the answers. Thank you for reading.

Valerian Texeira

St. Joseph Nagar

Mangalore 575002

Last edited on3-3-2011, 18-3-2011 for keeping it on working condition

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