Archive for May, 2019

The SSL Certificate of Damocles

Tuesday, May 14th, 2019

Ever since I “upgraded” this website to use SSL, it’s become completely inaccessible once every three months, because the SSL certificate expires. Several years in, I’ve been unable to find any way to prevent this from happening, and Bluehost technical support was unable to suggest any solution. The fundamental problem is that, as long as the site remains up, the Bluehost control panel tells me that there’s nothing to do, since there is a current certificate. Meanwhile, though, I start getting menacing emails saying that my SSL certificate is about to expire and “you must take action to secure the site”—never, of course, specifying what action to take. The only thing to do seems to be to wait for the whole site to go down, then frantically take random certificate-related actions until somehow the site goes back up. Those actions vary each time and are not repeatable.

Does anyone know a simple solution to this ridiculous problem?

(The deeper problem, of course, is that a PhD in theoretical computer science left me utterly unqualified for the job of webmaster. And webmasters, as it turns out, need to do a lot just to prevent anything from changing. And since childhood, I’ve been accustomed to countless tasks that are trivial for most people being difficult for me—-if that ever stopped being the case, I’d no longer feel like myself.)

On the scientific accuracy of “Avengers: Endgame”

Friday, May 3rd, 2019

[BY REQUEST: SPOILERS FOLLOW]

Today Ben Lindbergh, a writer for The Ringer, put out an article about the scientific plausibility (!) of the time-travel sequences in the new “Avengers” movie. The article relied on two interviewees:

(1) David Deutsch, who confirmed that he has no idea what the “Deutsch proposition” mentioned by Tony Stark refers to but declined to comment further, and

(2) some quantum computing dude from UT Austin who had no similar scruples about spouting off on the movie.

To be clear, the UT Austin dude hadn’t even seen the movie, or any of the previous “Avengers” movies for that matter! He just watched the clips dealing with time travel. Yet Lindbergh still saw fit to introduce him as “a real-life [Tony] Stark without the vast fortune and fancy suit.” Hey, I’ll take it.

Anyway, if you’ve seen the movie, and/or you know Deutsch’s causal consistency proposal for quantum closed timelike curves, and you can do better than I did at trying to reconcile the two, feel free to take a stab in the comments.

A small post

Friday, May 3rd, 2019
  1. I really liked this article by Chris Monroe, of the University of Maryland and IonQ, entitled “Quantum computing is a marathon not a sprint.” The crazier expectations get in this field—and right now they’re really crazy, believe me—the more it needs to be said.
  2. In a piece for Communications of the ACM, Moshe Vardi came out as a “quantum computing skeptic.” But it turns out what he means by that is not that he knows a reason why QC is impossible in principle, but simply that it’s often overhyped and that it will be hard to establish a viable quantum computing industry. By that standard, I’m a “QC skeptic” as well! But then what does that make Gil Kalai or Michel Dyakonov?
  3. Friend-of-the-blog Bram Cohen asked me to link to this second-round competition for Verifiable Delay Functions, sponsored by his company Chia. Apparently the first link I provided actually mattered in sending serious entrants their way.
  4. Blogging, it turns out, is really, really hard when (a) your life has become a pile of real-world obligations stretching out to infinity, and also (b) the Internet has become a war zone, with anything you say quote-mined by people looking to embarrass you. But don’t worry, I’ll have more to say soon. In the meantime, doesn’t anyone have more questions about the research papers discussed in the previous post? Y’know, NEEXP in MIP*? SBP versus QMA? Gentle measurement of quantum states and differential privacy turning out to be almost the same subject?