Experiments with entangled photons have been awarded the prize in physics.
We need to understand how these experiments settled a long-running debate among physicists. John Bell is an Irish physicist.
Bell was able to translate a question about the nature of reality into a physical question that could be answered by science.
There is quantum entangled matter.
We know that quantum objects have properties we don't normally associate with ordinary objects. Light is either a wave or a particle. We don't have a fridge that does this.
There are two broad types of explanation we can imagine for this type of behavior. It's possible that we see the quantum world the same way we see the real thing. We can't see quantum reality clearly because our view of it is distorted.
Physicists were divided about which explanation was correct. Some people thought that the quantum world was unusual. Albert Einstein was one of the people who thought the quantum world must be the same as the ordinary world.
The prediction of quantum theory is at the center of this division. The properties of certain quantum systems that interact remain dependent on each other even when the systems have been moved a long distance apart.
In 1935, the year he came up with the idea of trapping a cat in a box, Schrdinger came up with the termentanglement. He said it's ridiculous to think the world works this way.
There is a problem with entangled objects.
It would appear that quantum entangled systems are communicating with each other instantly if they remain connected. Einstein's theory of relativity does not allow this type of connection. Einstein thought this idea was spooky.
In 1935, Einstein, along with two colleagues, created a thought experiment that showed that quantum mechanics can't give us everything we want. There must be something more to the world than we know.
As time went on, the question of how to interpret quantum theory became a footnotes. In the 1940s, many of the best minds in quantum physics were using the theory to build the atomic bomb.
It wasn't until the 1960s that the scientific community realized that there was a solution to the problem ofentanglement.
Bell's Theorem is a famous one.
Bell used an entangled system to extend Einstein's 1935 thought experiment. There was no way the quantum description could be incomplete and still match the predictions of quantum theory.
It seems that the news for Einstein is not good. This was not an easy victory for his opponents.
In the 1960s, it wasn't clear if the predictions of quantum theory were right. To prove Bell's point, someone had to transform the argument into a physical system.
This is where two of this year's prizewinners begin their stories. The experiments performed on Bell's proposed system show the predictions of quantum mechanics to be accurate. There is no further account of entangled quantum systems that can describe the observed quantum world if we don't accept spooky action at a distance.
Is Einstein right?
The advances in quantum theory seem to have shown Einstein to be incorrect. We don't have a foggy view of a quantum world that is similar to our ordinary world.
It's too simplistic to think that we see an inherently unusual quantum world. One of the key philosophical lessons of this episode is provided by this.
We don't know if we can talk about the quantum world beyond what we know about it.
The distinction between reality and our knowledge of reality can't be made. It's not possible to refer to reality without using the information we have.
Our ordinary picture of the world is no longer supported by this distinction. We owe John Bell a great deal.
Let's hear it for John Bell though. I mean Christ, really. It was thanks to him that quantum foundations became experimental physics and not philosophy. (Nothing against philosophy, but it's good to get answers sometimes.)
— Philip Ball (@philipcball) October 4, 2022
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