The Most Beautiful Experiment
Quantum physics informs us that a system exists in superposition — that is, in all possible states — until we observe that it is only in one specific state.
According to a 2002 poll of Physics World readers, the “most beautiful experiment” in physics is one that simply and elegantly demonstrates how observation affects quantum systems: The double slit experiment. The double slit sets aside causality, determinism, and the notion that reality is “out there” as it blurs the line between the observer and the system being observed.
In the double slit experiment, a series of single photons (light particles) are fired at a solid plate that has two slits. On the other side of the solid plate, a photographic plate is set up to record what comes through those slits.
The question: What will we see on the photographic plate?
The answer: If one neglects to observe which slit a photon passes through, it appears to interfere with itself, suggesting that it behaves as a wave by traveling through both slits at once. But, if one chooses to observe the slits, the interference pattern disappears, and each photon travels through only one of the slits.
The formation of the interference pattern requires the existence of two slits… But how can a single photon pass through two slits simultaneously? At that point, we are forced to consider each photon as a wave that travels through both slits… Or we have to think of the photon as splitting and going through each slit separately — and wondering how the photon “knows” a pair of slits is coming.
The only solution is to abandon the idea of a photon — or any other quantum system — as having a location in spacetime until it is observed.
I am trying to figure out the truth about the current understanding of quantum physics. From my understanding nothing can be measured without at some level interfering with what is being measured. Do you know the details of how they measured which slit the photon goes through and how it may interfere with the behavior of the photon? Thanks.
Re: Details: There have been numerous double-slit experiments carried out since the early nineteenth century — using light, neutrons, atoms, electrons, and even molecules as large as carbon-60 and carbon-70. Some were measured by human observers, and some recorded by detectors which were then observed by human observers — who, I might add, also conceived and built the detectors specifically for the purpose of later observation. So, while a real-time human observer is not needed for the experiment itself, it nevertheless holds that a detector’s results are observed, at some point, by a human. And so the effect occurs.
In QT circles, this phenomenon is known as the “measurement problem.” It’s also an ontological dilemma for many people. To my thinking, it seems a simple enough fact that everything we know about anything in this universe is a direct result of observation, for how could we “know” anything otherwise? From that perspective, it also makes sense that an observer (like, for instance, a human) will have an effect on any observable with which it interacts (like, for instance, a photon).
To quote one of my favorite physicists, Erwin Schrodinger, “Subject and object are only one. The barrier between them cannot be said to have broken down as a result of recent experience in the physical sciences, for this barrier does not exist.”
If you’d like to conduct the original experiment yourself, check out http://www.cavendishscience.org/phys/tyoung/tyoung.htm
what about the reductionist approach? suppose I eliminate one intelligent being after another…when I finally eliminate myself, will the universe ‘as we know it’ still exist? will the bullet which blew my brain, continue to follow a newtonian trajectory? I think yes.
You’re using reductionism to argue in favor of pluralism — neither of which can be reconciled with quantum theory. Although the conclusions you have drawn from your model are (superficially) intuitive, it is through deeper analysis that principles such as entanglement and complementarity have been uncovered — and, thus, the case for emergence/synergy successfully established.
Even macro-cosmically speaking (in this case, bullets and brain spatter), reductionism does not work within the ontological framework of QT, as uncertainties at the micro level are increased.
To quote Ernest Gellner, “Reductionism is rooted not in the nature of things, but in our ideal of explanation.”
I had trouble understanding this experiment at first, but on YouTube there is a cartoon like video from Fred A Wolf (Dr Quantum) than explained it perfectly. It was the understanding of this experiment and how consciousness plays such an active role in our realities that has me so turned on to QP. Love the site!
Thanks for your comment. If you are interested, I have a YouTube channel dedicated to exploring the Observer Effect, featuring over 230 videos at the present time (and I am always adding more!).
You can visit my channel at http://www.youtube.com/kellyneill
Yes, thank you- I’m really getting wrapped up in QP and now I know how I’ll be spending a good portion of tomorrow.
Have fun, Ross! Prepare to be astounded, wow’d, and to stumble upon as many or more questions than answers!
Thanks so much for providing this link. I am certain I have minimized my life experience by trying to live within the “laws of nature”. This quantum stuff is a blast.
Has anyone that you know of conducted the experiment to alter the observed effect with intent, rather than observing, actually manipulating the outcome by thought?
I was a chiropractor for horses, and on the journey of life figured out how to adjust, or heal by thought.
I realized that some of the misalignments of certain joints, particularly the Jaw, were being caused by my own observations, which eventually turned into a very common malady.
When I realized that I had created this outcome, I then changed my thought about this particular mis-alignment, afterwards, it has been a rare ocourence.
I guess now I would be considered a non observer to this particular joint.
We are given such a gift, so simple, that it seems phenomenally difficult.
My little story here is what prompts my question about the experiment.
Thank you, Love your work here and look forward to watching your youtube videos
Ted
Thank you, Ted.
I have had similar experiences using healing thoughts with both animals and people in my own life.
It’s great to know that someone else is observing observation in a similar fashion.
What could be the possible implication of this in ‘real life’ i.e in all practicality?
It throws materialism and determinism out of the “reality” question, because it demonstrates that “reality” exists solely as waves of information (possibilities) until we observe it in some way.
In terms of “practicality,” this means that we create reality by observing it.
It is hard for me to understand the implication of observation affecting reality. How is it that observation is defined? Is it to be able to perceive the outcome through our senses? What about when the subject in question (the photon) cannot be detected by our fundamental senses? Well, we can put a camera by the slit and record and data to extend our perception. But what if we put the camera there, but delete the data without looking at it? Have we still observed it?
If we were to do the same experiment with small marbles, why wouldn’t we get the interference pattern? You could say that we are observing the marbles as we see each of them go through a slit. Well, what if we all turn our backs to it, and cover our ears, so there is no way to know what path the marble took?
How do you define observation really?
The question you ask – “How do you define observation?” – is argued to this day among physicists and philosophers. It’s part of what makes this experiment so compelling.
I have been watching and thinking about many of the theories, The String Theory, M Theory, The Measurement Problem, etc. I like the idea about multi Universes and the Big Bang could strongly have come from two different universes membrains crossed paths or collided to create a new membrain/universe. This to me still makes me think that we’re part of something else even bigger.Outside the multiverses there is what I call a megaverse etc. This is what is very close to, what seems to me, that cells do. Is it speculated that when these two membrains collide, is it borrowing energy from each? kind like when a sperm meets an egg? or is it creating it’s own?
A few physicists believe that our universe was created by a “collision” type of event between two previously existent universes’ membranes, which disintegrated in the collision. They get a lot of press, because M-theory is sexy and new.
M-theory itself, however, is currently untestable and in physics, a theory is defined by its testability. And so many physicists consider M-theory to be more of a philosophical perspective than a workable physical theory.
What would happen if you cut the photographic plate in two, and moved one half closer to the slit directly in front of it? Wouldn’t that also constitute an observation (to see if the photon went through the corresponding slit) and ‘collapse the wavefunction’?
I am following you so far but I would like to take it a little further.
Question: Are they watching the screen as they perform this test, if so would that not be considered an observation and thus collapsing the wave function at that point in time rather that just at the detectors?
Question: The Delayed Choice experiment reveals that it can be observed and still provide an interference pattern, it is only when the data is know to the tester that the wave function collapses. So it would seem that it is not mere observation that alters the state but rather it is from our knowledge of it that reduces it from a wave to a particle. This does not deflate the experiment because it is by our observation that we come to know which slit it go through but it certainly complicates the issue and demands that we take it further as to just how we create our reality, is it just by our observation or is it through some deeper conscious act such as knowing? And if so, what does that mean?
Thanks in advance
Brian
Howard,
The double slit experiment is over 200 years old when Thomas Young first performed it in 1801 since then and in more recent times the experiment has been revised to your liking look up double slit delayed choice, it answers just exactly what you were talking about.
Interesting. It appears that small subatomic particles move in synchronicity with one another due to their wave vibrations matching as a function of their nature. Our own subatomic particles must vibrate at a rate close to the emission source in order to be detected by us allowing for thought waves to form and resonate at the same rate. Such an event would cause a synchronicity between ourselves and the particles. This is the first evidence for the reality of thought waves in physical space. It appears that particles this small are subject to connection with us. Larger objects tend to follow the law of relativity. The missing link is how gravity and larger object tie back into the smaller world of quantum mechanics. One possible explanation is that space can only hold so much “matter” in any one point in time. If the density of matter exceeds the carrying capacity at any one point in time, no matter how tiny, we get a temporal and thus dimensional shift, of equally tiny magnitude but of enormous scope. It is possible that concentrated thought waves could create a super miniature black hole and shift time and space for those around it into a new dimension very much like the one they left. It is also evident that vibrational levels determine the nature of the shift. Apparently like vibrations are attracted to like vibrations. We can create miniature worm holes that move us through time and space. If enough people have concentrated thoughts about the same thing over time, the worm hole can become quite large, perhaps becoming large enough to actually see at some point. All conjecture on my part, but interesting.
I’ve been reading about this for only a very short time, but it is probably the most interesting and beautiful thing I’ve ever come across. I been experiencing an appreciation for physics that I havn’t felt since before my teachers tried their very hardest to completely ruin it in school. I’ve been looking to do something more fulfilling, perhaps a physics degree wouldn’t be such a bad thing. This website is great, thankyou.
[...] all of life is connected by a common "frequency" that allows for a form of telepathy? The Most Beautiful Experiment the observer effect [...]
Quantum Physics - BulldogBreeds.com Forums said this on November 13, 2011 at 12:54 pm |
This relationship can only be described in a parable of the master and the slave.Every time the master looks away the slave goofs offs and does as he pleases,but when the master is looking the slave quickly realizes and becomes diligent again.This is great writing.nice pages:)
[...] on to the double slit experiment (worthy of a repeat here, and here) observing something materially affects it’s effect on the world. I repeat, [...]
I think that QM doesn’t say that a system exists in all possible states. I think that it says it can exist in any possible state. that is, according to the original 1930s statements that seem to be terribly misinterpreted.
then theres these baseless assumptions:
#photons are a single particle – despite the fact that they behave as if they were a tiny electromagnetic dipole.
#the photon must pass through both slits for interference to be generated – despite physicists having no idea how it happens.
This is an ontological question that has been debated since the 1930s, the answer to which entirely depends upon which QT interpretation you favor. The Copenhagen interpretation arose as a collection of varying and contradictory opinions among the top physicists at that time. Nevertheless, one opinion prevailed. Copenhagen holds that that any unobserved system exists in all possible states simultaneously – and is thereby existentially indeterminate.
Should “all possible states” apply only to those possible states that are distinguishable by observables? Bohr didn’t think so. I don’t think so.
Could one extrapolate from this that matter only exists when we are looking at it? Do we actually live in The Matrix? I actually get a little queasy thinking about this experiment and another one where a series of particles’ rotation rates are measured (after it has been proven that they slow down when observed but are the same normally) before a few are chosen for random observation in the second part of the experiment, the particles that WERE TO BE OBSERVED in the LATER STAGE of the experiment had ALREADY SLOWED DOWN before the first measurement! WHY?
Good questions.