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Quantum Entanglement

John Markoff at the New York Times has been heralding an experiment at Delft as disproving Einstein’s view of the universe. While I have my own issues with Einstein, I am not as impressed with the Delft demonstration as Markoff and others appear to be.

The quantum world is incredibly mysterious to us – we cannot observe its inner workings directly, but only observe its side-effects. This means that we can’t make statements about the behavior of any one system of particles, but only about many systems in aggregate.

Let me give a classical example. When we toss a coin in the air, we know that there is a fifty percent chance that it will land “heads up.” If we could measure the coin’s position and rate of spinning and also knew precisely the properties of the floor that it would land on, as it was in flight we could calculate precisely which way it would land. But we can’t do that, so we believe that there is an element of “chance” in the outcome. In the terminology of quantum mechanics, we might say that the coin in flight is in a “quantum” state: 50% heads up and 50% heads down.

Now let’s say that we put two people in a room and asked them to toss a coin. Since we can’t observe the thoughts in their mind, we might consider them to be in an “entangled” state. We know that if we ask one the answer, we’ll receive the same answer from the other We then separate them by miles and ask the first one what the result of the toss was. If she says “heads,” we know instantaneously that the second person will also say “heads.” So we might say that the state of the pair has “collapsed” to “heads” instantaneously, and we know what answer will be given by the second person.

But the information didn’t travel instantaneously from one to the other. The two people from the room knew all along what the answer was.

If this is actually the nature of quantum entanglement of very small particles such as electrons (the subject of the experiment in Delft), why do scientists become so confused about the process of information transfer?

That chance in coin tossing actually reflects the randomness of the tossing process: the position of the coin on our thumb, the effort of our muscles, the condition of the floor: only with great practice could we ensure that all of these were identical on each toss. If that investment in discipline were made, we could actually control the outcome of the toss, achieving heads 100% of the time.

Now let’s say that, unbeknownst to us, the coin tossers are actually trained in this skill. How would we find out? We couldn’t find out from one experiment. Even after a second experiment, there’s still a one-in-four chance that a random toss would achieve “heads” in both cases. No, we’d have to run many experiments, and decide how improbable the outcome would have to be before we accepted that something was wrong with our theory of coin tossing.

In other words, the confusion comes in because the philosophy of quantum mechanics confuses the problem of proving the correctness of the theory with the actual behavior of the particles that produce any specific outcome. In our coin-tossing case, the quantum theory holds that we’ll get heads 50% of the time. But to prove that, we have to do many, many experiments.

Let’s extend this to the problem of Schroedinger’s cat: a cat is in a box with a vial of poison gas and a radioactive isotope. When the isotope decays (at some random time), a detector triggers a hammer to smash the vial. In the “accepted” philosophy of quantum mechanics, the state of the isotope evolves over time, being partially decayed. This means that the state of the cat is also partially dead. When we open the box, its “wave function” collapses to one state or the other.

We can clarify this confusion with a thought experiment: In our coin tossing example, let’s say that we put coins in boxes and had children run around the room to shake them up, randomizing their state. In quantum mechanical terms, we would say that the state of any one coin was “50% heads.” When we look in a box, the state of that coin is determined: it’s wave function collapses to either heads or tails. It is only by observing all of the coins, however, that we can determine whether the children actually were successful in randomizing the state of the coins.

By analogy with this, we can only prove Schrodinger’s theorem about the “deadness” of cats by performing many experiments. At any instant, however, each cat in its box is either alive or dead. It is unfortunate that we’d have to kill very many of them to determine whether the theory of radioactive decay was correct.

So I side with Einstein: I don’t see any mysterious “action at a distance” in the experiment at Delft, and I certainly don’t see it as proof that information can travel faster than the speed of light.

My own proposition is very different: it is that the dark energy that permeates space and constrains the speed of light can have holes opened in it by the action of our spirit. Once it is removed, the barriers of time and distance fall. When such bonds are created through fear, the subject of the fear seeks to escape them, and the strength of the bond dissipates. When the bonds are created in love, the entanglement persists by mutual consent, and grows inexorably in strength and power, eventually sweeping all else before it.

What kind of confirmation could the physicists at Delft provide of this? I’m not certain, but it would be an experiment in which the electrons were separated, and a manipulation of one was reflected in the other. In our coin-toss experiment, it would be if the two people in the room were separated before the coin toss, and the second knew instantly what the result was of the toss performed by the other. From the video they made, I don’t think that’s what is happening at Delft.

This post in memoriam of Professor Eugene Commins who taught my upper-division course in Quantum Mechanics at UC Berkeley in 1981, and who benefited during his doctoral studies at Princeton from conversations with Einstein.

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