Quantum Bayesian Networks

August 18, 2015

Quantum Information meets Quantum Matter

Filed under: Uncategorized — rrtucci @ 10:16 pm
Hmm, quantum matter, So what is non-quantum matter?

Hmm, quantum matter.

So what is non-quantum matter?

What used to be called “strongly correlated quantum (many body) systems” has in the past decade been rebranded to “quantum matter”, a term that reminds me of the terms “black coal” or “canine dog”. The term “quantum matter” is so new that it still doesn’t have a Wikipedia entry.

In 1951, John C. Slater (inventor of “Slater determinants”) published a famous book called

“The Quantum Theory of Matter”

In 2015, a brilliant advance in the physics of word ordering has replaced that brand by

“The Theory of Quantum Matter”.

Nowadays, “The Theory of Quantum Matter” is quite the craze, and we now have Istituti of academics dedicated entirely to “Quantum Matter” as, for instance, the CTQM (Center for Theory of Quantum Matter) at the Univ of Colorado, Boulder.

“The Theory of Quantum Matter” promises to unify Matter and Information by unifying Quantum Information, String Theory and Condensed Matter Physics. Poor Ed Witten must be shaking in his boots (either from fear or laughter).

Recently, a group of Caltech students published in arXiv a preliminary version of their book entitled “Quantum Information Meets Quantum Matter” They described their book in a recent post in the blog Quantum Frontiers.

By the way, the blogs “Quantum Frontiers”, by Caltech, and “Shetl Optimized” by Scott Aaronson, are purportedly about quantum computation (QC) and quantum information (QI). In their blogrolls, they link to many blogs that have nothing to do with those topics and link to nearly inactive blogs like Quantum Pontiff, but they would never stoop down to link to this my 7 year old blog that is quite active and is dedicated exclusively to QI and QC. Just another example of the dirty tactics used by vain academics to crush the spirit of anybody whom they perceive as a threat to their divine royal rights.

An interesting aspect, at least to me, of the study of “quantum matter” is that it uses CMI (pronounced “see me”, Conditional Mutual Information) to study quantum entanglement in strongly correlated quantum systems. Let me make two simple points about CMI

(1)In general, CMI measures a mixture of both quantum correlations (aka, entanglement) and classical correlations (between two parties).

(2)If one takes a special limit of CMI, one obtains a quantity that measures quantum correlations exclusively. This quantity is now called squashed entanglement.

It turns out that I was the first person to point out that there is a connection between CMI and quantum entanglement and also the first person to define squashed entanglement. You can fact check this assertion from the references of the Wikipedia article on squashed entanglement. I did it all thanks to deep insights that I gained from the study of classical and quantum Bayesian Networks. People that use tensor networks instead of quantum Bayesian networks converged on squashed entanglement several years after I did, after looking at my papers. That is one of the many reasons why I believe that quantum Bayesian networks are better than tensor networks for doing quantum information theory. The software company artiste-qb.net that I work for is heavily involved in classical and quantum Bayesian Networks.


quantum bayesian networks: rikki-tikki-tavi the mongoose

quantum tensor networks: drunken cobra

Who wins?



  1. If I ever start a quantum blog, I will blogroll you fer sure, dude!

    Comment by Max Born — August 19, 2015 @ 4:47 pm

  2. Thanks Max.

    Comment by rrtucci — August 19, 2015 @ 4:59 pm

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