Some researchers may be close to performing experiments that can help define the most bizarre phenomenon in the universe called decoherence. Here is the article but I think I can do a much better job of explaining the idea.
What is Decoherence?
Over 100 years ago scientists discovered something that really confused them. This experimental evidence was so confusing they essentially punted on figuring it out and it has been 100 years and we have no better idea what the answer is.
What they discovered is that the universe seems to be able to operate 2 different ways but it chooses which way to operate at any particular moment based on whether we are looking at it.
That’s right. It seemed to depend on if humans were looking at the results or not. If we didn’t look the universe operated one way which was incredibly different than if we looked.
In one way the particles and energy would be distributed like waves on the ocean existing over a wide space. Every single particle stretching for miles in every direction like the wave hitting a beach. Where it hit the beach depending on what crest of the wave happened to hit the beach first.
In the other way the universe acted like billiard balls and had definite position in space. When we looked the universe looked like billiard balls. When we don’t look the universe seems to spread out and act like anything can happen anywhere.
Einstein was firmly against the wavelike reality and said god didn’t play dice. He spent more than a decade trying to disprove this idea and failed.
This was called the measurement problem. This refers to the idea that when you go to measure something the world changes right underneath you as if it knew you were observing it. Since you can’t observe the world in its fuzzy state it has been hard to figure out when exactly this transition happens.
You may say well what proof do you have that the world acts like this wavy thing anyway? Maybe you’re just making that up. Actually the experiment was extremely simple. If we shoot electrons at a wall using a single hole in a plate between the shooter and the wall to receive the electrons we get a pattern that looks as we would expect which is a big pileup of electrons right behind the hole on the wall and then fewer and fewer as we get farther from the hole.
If we shoot the electrons at a wall with two holes in the plate we get pile ups of electrons behind the two holes but between the two holes and outside the holes we get a pattern that looks exactly like electrons are canceling each other somehow (even though they are sent at different times) as if one electron knew where all the other electrons had gone before.
The use of one hole means we know that the electron must have gone through that hole. Whether we actually observed the electrons going through the hole nature acts based on our knowledge not even the act of observation. Simply knowing that the electron had to go through the hole caused decoherence and acting like it was bullets.
We have also constrained the problem through a thought experiment created by a physicist named Bell that was turned into real experiments. Bell’s inequality proves that nature acts non-locally (as in the wave part).
Other than this we have basically made no advances in this theory for 100 + years. Feynman one of the most brilliant physicists who brings simplicity to the most complicated physics said forget trying to understand the decoherence problem. Just use the formulas. Don’t try to think how it could actually be true and work. Just do the math.
Roger Penrose who I think is the smartest man ever built an entire theory called twistors to help explain this but the theory is unproved although recent stuff has found twistors extremely useful and accurate. He also created quantum gravity. Penrose believes that gravity causes decoherence.
Over 74 theories have come out to explain the measurement problem or decoherence but none has proven compelling. Most surveys of physicists have shown the “multi-worlds” theory is the leading theory but all the answers have problems.
The experiment to help resolve the question may be on the horizon
I don’t believe this experiment will tell us the answer but it will definitely eliminate some.
The experiment is as follows:
1) We take a nitrogen carbon moleculeS we call nanodiamonds and entangle them.
2) We cool the nanodiamond molecules to 1 one millionth of a degree Kelvin (Absolute zero.)
3) We shine a laser tweezer at the nanodiamond to elevate them to a higher state and levitate them in space using the tweezer as a levitation beam.
4) While the nanodiamond are in the higher state they are in the coherent phase entangled as we say. We see how long it takes for them to decohere when we remove the tweezer.
We can make the nanodiamond easy enough and entangle them. The levitating tweezer laser was invented in the 70s and just this year 2018 coincidentally was awarded a Nobel prize!
The last problem is getting so close to absolute zero. So far we have demonstrated the ability to get to 1/10,000th of a degree. Getting to 1 one-millionth is not trivial I am sure but the researchers seem to think it is a very solvable engineering problem.
Whoever can build this experiment and cool the nanodiamond to 0.000001K can then measure the decoherence rate.
The first thing we would do is to measure how fast and frequently the nanodiamond falls out of coherence.
This would be the first observation of the decoherence event. Well we wouldn’t be observing it but we would be able to put some constraints on which of the decoherence theories could be correct. If the rate happens at the rate that Penrose’s quantum gravity theory predicts it will put a lot of things into the air.
Quantum gravity is not the most favored theory by physicists.
One of the predictions of quantum gravity conflicts with the inflationary theory of the standard model. In quantum gravity the universe expands and contracts in epochs. Penrose announced that he had discovered evidence of these epochs in the residual background radiation of the universe we observed 20 years ago. Other physicists say the evidence is inconclusive.
Quantum gravity says that the thing that causes decoherence is when the energy in an entangled system exceeds the size of one quanta of gravity which is related to the smallest mass then decoherence will occur.
Penrose used quantum gravity to compute the duration of brain waves under the assumption that microtubules in the brain at synapses were in coherence and that the brain was a quantum computer. He was able to show a reason for the duration and variation in brain waves which no other biologist or theoretician has any explanation for.
This experiment will be incredibly exciting and help resolve a 100 year old question in physics which has baffled physicists for all this time and led to the befuddlement of the greatest minds in history. It is a fundamental problem that makes us question our ability to understand reality and if our theories are all correct or simply a coincidence.