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Posted by on May 23, 2011 in Some reminiscences | 0 comments

Life after NMR : My Journey to Quantum Weirdness

A Quantum Question

After years of studying Nuclear Magnetic Resonance, and deciding that I wanted something different, I started to look around. Since I knew a bit about spins, and quantum information theory was getting hot, I looked in that direction at first.  In 1993, Bennett et al had already published a paper about quantum teleportation; quantum computing using qubits (quantum bits) was being developed, motivated by Shor’s algorithm; and experimental evidence was being produced confirming quantum teleportation and quantum cryptography.  Since they all used spin, albeit of photons, I started to read the papers.

Very quickly I was introduced to Alice and Bob, the fictitious couple who represented points A and B in these experiments (and Charlie was introduced for point C). Many results had been published using: two photons (Einstein Podolsky Rosen (EPR) experiments); three photon experiments (teleportation); quantum erasure experiments and others involving more clusters of entangled photons. These ingenious experiments are a challenge both technologically and theoretically. I have spoken with many of the scientist who did these experiments, and every one declares that they do not understand the mechanism behind their results.

As I looked deeper into this area, there were troubling issues that I could not accept.  First entanglement is supposed to persist to space-like separations. Therefore if one spin is flipped on Earth, the other will instantaneously flop many light-years away. How? Non-locality was established as a property of Nature and is so firmly entrenched now by Bell’s theorem that major journals, like Physical Review Letters, adopted an editorial policy to reject without external review any paper that questions it (The editor who told me this was Dr. Garisto of PRL).

But no one understands non-locality.

The point is, it makes no physical sense to believe that entanglement persists to non-local separations, and no one can give a cogent explanation. Rather scientist try to evade the issue by invoking quantum weirdness.

By the way, it was Schrödinger in 1935 who said that entanglement is not “a” property of quantum mechanics, but “the” property. It was he who coined the term entanglement.

Well maybe I am being stubborn and maybe I should accept that non-locality is a property of Nature.  However it is the most worrying aspect of quantum mechanics, an otherwise fantastically successful theory of the microscopic.  It has got to the point that since no answer has yet been found, the vast majority of physicists (I believe grudgingly) accept the statistical nature of the microscopic and believe indeed that God does play dice.

But I am not yet convinced.

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