In DepthQuantum Mechanics

Breakthrough lost in coin toss?

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Science  03 Oct 2014:
Vol. 346, Issue 6205, pp. 22-23
DOI: 10.1126/science.346.6205.22

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For 26 years, physicists have argued over an unorthodox quantum measurement technique that seems to circumvent one of the central tenets of quantum mechanics. "Anomalous weak values" bend the rule that you can't measure a quantum particle without disturbing it, devotees say, and provide deep insights into quantum reality. Skeptics counter that the whole enterprise is just standard quantum mechanics misinterpreted. Now, two theorists say that anomalous weak values aren't even a quantum phenomenon. To prove it, they propose a thought experiment in which two people, Alice and Bob, produce an anomalous weak value classically, by exchanging a coin. The theorists argue that because anomalous weak values aren't inherently quantum mechanical they offer no novel insight into the quantum realm. The inventors of the technique dismiss the analysis.