Happy Birthday Schrödinger & Cat.
I caught the gladiator gang sign adorning this entangled pair at D-Wave Systems, the quantum computer company. (And with a nod to the multiverse, I named our investment vehicle for this company Parallel Universes, LLC.)
And I just read a fine bender on the plane today, on Schrödinger’s birthday no less. It starts with the classic challenge of entangled photons, where the observation of one resolves the other spontaneously, even when they are great distances apart, and any information transfer between them would have to travel over 10,000x faster than the speed of light. Well, physicists keep pondering this (and trying real hard to avoid Deutsch’s simple solution: parallel universes):
“Reality, relativity, causality or free will? Take quantum theory at face value and at least one of them is an illusion – but which? The culprit, as usual when we find ourselves assailed by doubt and racked with existential fear, is quantum theory.
We would have weird situations, weird violations of causality, if there were superluminal signaling [between entangled photons]. Any faster-than-light channel might also be open to hijacking for nefarious purposes: you could use it to transmit information backwards in time. Allow violations of relativistic causality, and we could all be lottery millionaires.
There is no story in space and time that tells us how the correlations happen. There must exist some reality outside of space-time.
Just as quantum particles can be in two or more places at once, so seemingly can those particles be in two or more moments at once. The system can be simultaneously in the states “Alice came into the room before Bob” and “Bob came into the room before Alice”.
Causal order is not a fundamental property of nature. Causality is only restored when the parameters of the experiment are tweaked to make the particles less entangled with each other, behaving more like familiar, classical particles. We live in space-time, and experience causal order within it, yet causal order is not apparently fundamental to quantum theory. If we accept quantum theory as the most fundamental description of reality that we have, it means that space-time itself is not fundamental, but emerges from a deeper, currently inscrutable quantum reality.
We are still hopelessly anthropocentric. The growing disconnection between our experience of the world and the results of quantum experiments are simply a modern version of the ever-more complex epicycles that Ptolemy and those who followed him used to explain the motions of the heavenly bodies. The problem back then was that we could only see the planets as revolving around Earth; it took Copernicus to turn things around, and suddenly all was plain and simple.
Perhaps we have constructed theories such as relativity and quantum theory with a similarly limited view, in thrall this time to a sense of space and time that might not exist beyond ourselves. We think time and position and so on are important variables for describing the world because we evolved to perceive them. But whatever is going on down there doesn’t seem to worry about them at all.”
From “Quantum weirdness: The battle for the basis of reality” http://www.newscientist.com/article/mg21929282.100-quantum-weirdness-the-battle-for-the-basis-of-reality.html
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