Tag Archives: Brian La Cour

Classic Quantum Confusion

Paris_Tuileries_Facepalm_statueBy now I am pretty used to egregiously misleading summarization of physics research in popular science outlets, sometimes flamed by the researchers themselves. Also self-aggrandized, ignorant papers sneaked into supposedly peer reviewed journals by non-physicists are just par for the course.

But this is in a class of it's own.  Given the headline and the introductory statement that "a fully classical system behaves like a true quantum computer", it essentially creates the impression that QC research must be pointless. Much later it sneaks in the obvious, that an analog emulation just like one on a regular computer can't possibly scale past 40 qubits due to the exponential growth in required computational resources.

But that's not the most irritating aspect of this article.

Don't get me wrong, I am a big fan of classical quantum analog systems. I think they can be very educational, if you know what you are looking at (Spreeuw 1998).  The latter paper, is actually quoted by the authors and it is very precise in distinguishing between quantum entanglement and the classical analog. But that's not what their otherwise fine paper posits (La Cour et al. 2015).  The authors write:

"What we can say is that, aside from the limits on scale, a classical emulation of a quantum computer is capable of exploiting the same quantum phenomena as that of a true quantum system for solving computational problems."

If it wasn't for the phys.org reporting, I would put this down as sloppy wording that slipped past peer review, but if the authors are correctly quoted, then they indeed labour under the assumption that they faithfully recreated quantum entanglement in their classical analog computer - mistaking the model for the real thing.

It makes for a funny juxtaposition on phys.org though, when filtering by 'quantum physics' news.

Screenshot 2015-05-28 01.35.43

The second article refers to a new realization of Wheeler's delayed choice experiment (where the non-local entanglement across space is essentially swapped for one across time).

If one takes Brian La Cour at his word then according to his other paper he suggest that these kind of phenomena should also have a classical analog.

So it's not just hand-waving when he is making this rather outlandish sounding statement with regards to being able to achieve an analog to the violation of Bell's inequality:

"We believe that, by adding an emulation of quantum noise to the signal, our device would be capable of exhibiting this type of [Bell's inequality violating] entanglement as well, as described in another recent publication."

Of course talk is cheap, but if this research group could actually demonstrate this Bell's inequality loophole it certainly could change the conversation.