Imagine opening the paper of the week for Sudoku and looking for puzzle pages. You’ll spend your mornings dealing with this logic puzzle, only to realize from the last few squares that there’s no consistent way to finish it.
You think, “I must have made a mistake.” So you try again, starting from the corner you couldn’t finish this time and work back the other way. But the same thing happens again. You’re down the last few squares and there’s no exact compromise.
According to quantum mechanics working the basic nature of reality is a bit like the impossible sudoku. No matter where we begin with quantum theory, we always end up with an enigma that forces the world to rethink what works fundamentally. (This is what makes quantum mechanics so enjoyable.)
I take you on a short tour through the eyes of a philosopher in the world according to quantum mechanics.
1. Spooky action at a distance
As far as we know, the speed of light (about 300 million meters per second) is the ultimate speed limit of the universe. Albert Einstein famously laughed at the possibility of physical systems affecting each other faster than light signals.
In the 1940s, Einstein called this “spooky action-a-distance.” While quantum mechanics had previously appeared to predict such spooky moves, he argued that theory should not be completed yet, and some good theory would tell the true story.
We know that there is a lot of potential for such a better theory. And if we think that the world is made up of defined, independent pieces of “material”, then our world must become one where the spooky action of the distance between these pieces of material is allowed.
2. Oose our grip on reality
“What if the world is not made up of well-defined, independent pieces of ‘content’?” I will hear you say. “Then can we avoid this spooky action?”
Yes we can. And many in the quantum physics community think the same way. But this is no consolation to Einstein.
Einstein had a long discussion with the Danish physicist Niels Bohr on the same question. Bohr argued that we should really abandon the idea of better defining the content of the world, so that we could avoid spooky action from a distance. In Bohr’s view, the world does not have specific properties unless we look at it. Bohr thought when we weren’t looking, the world we know isn’t really there.
But Einstein insisted that the world must be created Something Then whether we like it or not, otherwise, we can’t talk to each other about the world, and therefore science too. But Einstein could not have both a definite, independent world and a spooky action of distance … or could he?
3. Back to the future
The Bohr-Einstein debate is a reasonable fare in the history of quantum mechanics. The foggy corner of this quantum logic puzzle is less familiar, where we can save both a determined, independent world and no spooky action. But we need to be weird in another way.
If an experiment was done in the lab to measure the quantum system that could affect someone like the system before the measurement, Einstein could keep his cake and eat it too. This hypothesis is called “retroactivity” because the effects of experimenting have to travel “backwards in time.”
If you think this is weird, you are not alone. This is not a very common view in the quantum physics community, but there are supporters as well. If you have to accept spooky action at some distance, or like a world when we don’t see it આપણે we don’t know it, euphemism doesn’t seem like such a fantastic option.
Olymp. No votes from Olymp Limps
Imagine Zeus topping Mount Olympus in a world survey. Imagine being able to see everything that happened and will happen everywhere and for all time. It is called the “view of God” of the world. It is natural that there must be some way in the world, even if it can only be known by the omniscient God.
Recent research in quantum mechanics suggests that even in theory, God’s view of the world is impossible. In some bizarre quantum scenarios, different scientists can look carefully at the systems in their labs and make a complete recording of what they see – but they will disagree about what happened when it comes to comparing notes. There may be some definite fact in this matter about who is right – even Zeus did not know.
So the next time you encounter an impossible sudoku, make sure you are in good company. The whole quantum physics community, and maybe even Zeus knows how you feel.
Peter Evans is an ARC Discovery Early Career Research Fellow at the University of Queensland.
This article was first published on Conversation.
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