(Roughly) Daily

“Reality leaves a lot to the imagination”*…




Here’s a curious thought experiment. Imagine a cloud of quantum particles that are entangled—in other words, they share the same quantum existence. The behavior of these particles is chaotic. The goal of this experiment is to send a quantum message across this set of particles. So the message has to be sent into one side of the cloud and then extracted from the other.

The first step, then, is to divide the cloud down the middle so that the particles on the left can be controlled separately from those on the right. The next step is to inject the message into the left-hand part of the cloud, where the chaotic behavior of the particles quickly scrambles it.

Can such a message ever be unscrambled?

Today, we get an answer thanks to the work of Adam Brown at Google in California and a number of colleagues, including Leonard Susskind at Stanford University, the “father of string theory.” This team shows exactly how such a message can be made to surprisingly reappear.

“The surprise is what happens next,” they say. After a period in which the message seems thoroughly scrambled, it abruptly unscrambles and recoheres at a point far away from where it was originally inserted. “The signal has unexpectedly refocused, without it being at all obvious what it was that acted as the lens,” they say.

But their really extraordinary claim is that such an experiment throws light on one of the deepest mysteries of the universe: the quantum nature of gravity and spacetime…

Quantum entanglement, and what it might tell us about quantum gravity– the fascinating story in full: “How a tabletop experiment could test the bedrock of reality.”

[The arXiv paper on which this article reports, “Quantum Gravity in the Lab: Teleportation by Size and Traversable Wormholes,” is here.]

* John Lennon


As we contemplate connection, we might spare a thought for George Boole; the philosopher and mathematician died on this date in 1864.  Boole helped establish modern symbolic logic– he created symbols to stand for logical operations– and an algebra of logic (that is now called “Boolean algebra”).  Boole made important contributions to the study of differential equations and other aspects of math; his algebra has found important applications in topology, measure theory, probability, and statistics.  But it’s for the foundational contribution that his symbolic logic has made to computer science– from circuit design to programming– that he’s probably best remembered.


Happy Birthday (1894), James Thurber!!


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