Saturday links 19-Jan-2019: Gravitization of quantum mechanics, Revolt of the public, income sharing for tuition, Big 5 personality quiz

1. Roger Penrose on the gravitization of quantum mechanics. Physicist Roger Penrose was on Sean Carroll’s podcast (recommended). I want to highlight a particular point Penrose made at the 1:16 mark. As you may know, the theories of gravity and quantum mechanics are not reconciled. The problem is general relativity (gravity) treats space as continuous, not quantized. While quantum theory makes all interaction quantized.

One approach is to reformulate gravity to match quantum mechanics. This approach is called quantizing gravity. String theory is an example. Testing String theory (unless an indirect method is discovered) requires getting down to the Planck scale (very tiny, meaning super energetic particles). As Penrose put it on the podcast, it would require a particle accelerator the size of the solar system. Indeed.

Penrose argues we should go the other way around. Rather than reformulate gravity to match quantum mechanics, reformulate quantum mechanics to match gravity. This approach is call the gravitization of quantum mechanics (see paper). Penrose said testing this is just about within experimental reach now, using bose einstein condensates.

So what’s the point here? Funding, funding, funding! The world’s largest particle accelerator is the Large Hadron Collider (LHC) at CERN. CERN has just announced a proposal for an even larger collider, at the cost between €9 and €21 billion. Sabine Hossenfelder argues “it would make more sense to put particle physics on a pause and reconsider it in, say, 20 years to see whether the situation has changed, either because new technologies have become available or because more concrete predictions for new physics have been made.” Exactly so. I have no idea if Penrose’s ideas on the gravitization of quantum mechanics will pan out, but at least we can test them for way less than €9 billion.

2. A good Bandersnatch move review. Bandersnatch is a Netflix movie (technically an episode of Black Mirror) that lets you interactively make choices, resulting in different endings, depending on what you pick. I enjoyed this review more than the movie itself, since it clarified why video games are better suited for interactivity than movies. Here’s one bit:

The reason that letting the audience choose its own story keeps failing when the entertainment industry tries it is that it’s a bad idea. It’s the author’s job to write the story. They can then choose a way to convey that story that gives the reader freedom in how they experience it. But if the story itself is merely a loose collection of different options, each in a different genre and with a completely different tone, then what they’ve created isn’t a coherent work, but a self-indulgent mess—like “Bandersnatch”, in fact.

3. Martin Gurri’s book The Revolt of the Public. I’m about halfway through and it’s excellent (link). Gurri explains why internet publishing has led to nihilistic worldwide populist revolts. I’ll write more once I’m done. In the meantime, here’s a paragraph that captures the core idea:

The information balance of power has changed, of course. A generation ago, the public could exist only as a passive audience Information was dispensed on the industrial model: top down and one to many. That was the great age of the daily newspaper and famous anchormen on the model of Walter Cronkite. The advent of digital platforms, in a sense, created the public. People from nowhere, free of institutional entanglements, pushed the elites out of the strategic heights of the information sphere. Almost immediately, great institutions in every domain of human activity began to bleed authority a process that, as we have seen, in now approaching the terminal stage for many of them. That is my thesis for the revolt of the public.

4. CRISPR gene editing can’t make super-smart babies. This is a pretty basic point, but worth making since gene editing has been in the news. CRISPR/Cas9 gene editing is err prone, resulting in “off target” effects. So editing a single gene works only because you can make multiple attempts, starting over until you get it right. But complex traits like height or IQ are highly polygenic, depending on 1000s of genes. With each gene of very small effect. And editing 1000s of genes isn’t practical. At least for now, it won’t work. link

5. Telecoms companies sell user data to third parties. While many are upset about Facebook privacy, telecom companies are worse. If you care about this kind of thing, this article title says it all: I Gave a Bounty Hunter $300. Then He Located Our Phone.

6. NCAA should allow college athletes to cash in on endorsements. Financial exploitation of college athletes in big name sports is a tricky topic. But this seems like a good way to finesse the problem. Let Nike pay them. link

7. Income sharing to pay college tuition. The way income sharing works is you pay no college tuition up front. Then after you graduate, if you make above a threshold, you pay a fraction of your income for several years. Quote:

Lambda School gives students three payment options. They can either pay $20,000 upfront, pay $10,000 upfront and forgo 17 percent of their salary for a year (with the maximum payment capped at $15,000) or pay zero dollars upfront and forgo 17 percent of their salary for two years (with the maximum payment capped at $30,000). Allred estimates that more than 90 percent of students have opted to pay via an income share agreement.

It’s easy to dismiss this as no big deal. Why would paying before versus after graduation matter? And the New York Times piece is full of hype. But if you believe incentives are critical to making an organization perform, you can see why colleges getting paid depending on someone’s post college job success could be transformational. Incentives are critical. For example see Austen Allred talking about how the school is helping disadvantaged kids do better at job search. On the flip side, I think there’s also an incentive not to get students enrolled in programs where there’s no chance they’ll graduate. That seems harsh, but the current incentives are to enroll and accumulate debt, which is worse. Better to align all students to the programs that will help their careers the most, rather than over promise. Aligned incentives are great!

8. Personality quiz based on big 5 traits. Personality quizzes are normally junk science. And yes, that includes the popular Myers-Briggs test. Psychology breaks personality into the “big 5” traits: extraversion, agreeableness, conscientiousness, negative emotionality and openness to experience. 538 published an online quiz. It’s quick and fun to take. I got no surprises back. I’m more disagreeable and introverted than most. But very open to new experience. A good fit for writing about cool things on the internet, if I may say so. 🙂 Here’s the 538 test if you want to give it a try: link

And that’s all for this week. Thank you for reading!

Categorized as Link post

By Nathan Taylor

I blog at on tech trends and the near future. I'm on twitter as @ntaylor963.


  1. Penrose is a bit of a kook to be honest. I have struggled with his book “Road to Reality” and he just views things differently from most physicists. That’s not a bad thing we need unique views it helps science but his idea on what a spinor is should not be taken as the current view of how science works. I think Nima Arkani-Hamed gives you a much better view of how most of the string theorists think about the field. Anyway “The problem is general relativity (gravity) treats space as continuous, not quantized” is not how I think most physicists would put it. There’s no real need for gravity to be discrete and in fact if you look at the equations of QM, there’s no discreteness in the actual formula’s like Dirac’s formula. The quantification appears naturally when you solve the equations for a specific solution, in much the same way that eigenvectors and eigenvalues will naturally appear when you solve physics favorite problem the simple harmonic oscillator, but there’s no actual quantization in the formulas. The way Nima puts the problem between QM and relativity is this way: You use more and more energy to probe smaller and smaller distances. At a particular distance, if you put enough energy to probe that distance you create a black hole. Then if you try to probe even more all that happens is the black hole gets bigger. My favorite solution to this problem is the simplest solution asymptotic safety, which is a fancy way to say use math to renormalize general relativity. This would leave QM completely intact and not solve any problems with dark matter or dark energy nor the hierarchy problem. String theory is so ambitious that it not only solves all physics problems it contains within it every single version of QM which is possible. Loop quantum gravity is almost as ambitious. String theory of course does not quanticize space or time. It merely extends quantum field theory so that strings interact with other strings and this gets rid of the infinities. By the way if you go back and look at how the electron dipole moment was calculated by QFT, you should notice that it too had infinities. For a while there was no way out and quantum field theory was nearly abandoned over the impossibility of getting rid of the infinities. What happened is thanks to a combination of perturbation theory and renomalization physicists decided what the hell we’ll just divide infinity by infinity and get a finite result! And lo and behold it worked. You do need to grab a real world measurement in order to figure out exactly how to renormalize properly but once you do that QFT has become the single most accurate theory in science. Now you can’t just renormalize QFT and relativity the reason being instead of a simple infinity you have an infinite number of infinite infinities. That’s why the problem is so difficult. If you go back and listen to Nima Arkani-Hamed he will tell you that either general relativity or quantum field theory is not fundamental. And since general relativity is a derived theory, that leaves QFT. Remember what I said earlier that string theory was just a framework that includes all version of QFT that could possibly exist. So this means that string theory also has to be wrong. What is the right theory? Nima would say we have no idea. Or it could just be the plain simple idea of fix the awful infinities, and give up on the theories of everything at least for now. Sean Carrol is of course very mainstread, but he’s much too polite to call out Penrose when he varies from what most string theorists would say is necessary for string theory to work.

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