[Fis] Experimental verification of an indefinite causal order

[Steven Ericsson-Zenith]

Experimental verification of an indefinite causal order

"Investigating the role of causal order in quantum mechanics has recently
revealed that the causal relations of events may not be a priori well
defined in quantum theory. Although this has triggered a growing interest
on the theoretical side, creating processes without a causal order is an
experimental task. We report the first decisive demonstration of a process
with an indefinite causal order. To do this, we quantify how incompatible
our setup is with a definite causal order by measuring a “causal witness.”
This mathematical object incorporates a series of measurements that are
designed to yield a certain outcome only if the process under examination
is not consistent with any well-defined causal order. In our experiment, we
perform a measurement in a superposition of causal orders—without
destroying the coherence—to acquire information both inside and outside of
a “causally nonordered process.” Using this information, we experimentally
determine a causal witness, demonstrating by almost 7 SDs that the
experimentally implemented process does not have a definite causal order."

http://advances.sciencemag.org/content/3/3/e1602589

A valuable contribution, if repeated elsewhere.

Steven


--
    Dr. Steven Ericsson-Zenith
    Research Scholar - +1 650 308 8611
    Los Gatos, California. steven at iase.us
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