It's only a B, but still..

I recently took (and surprise, surprise, completed) a course on edX. Things like that will be old news to many by now, but this is the first time I used a MOOC, so I thought I should record my impressions.

The course in question: 'Quantum Information Science I, Part I', given by Prof. Peter Shor and Prof. Isaac Chuang, giants of the field from MIT. Prof Shor is the discoverer of one of the best known quantum algorithms and Prof Chuang is, among other things, coauthor of the definitive textbook of the field. There was one long talk by Charles Bennett too, another giant and a pioneer of quantum cryptography, and which was certainly one of the best ones from the whole course.

The course was divided in three subunits (you can see the syllabus here), each with a set of lecture clips, concept questions and problems. While I had not studied this area before, I was not totally ignorant of it either and my chief concern was the amount of mathematics that would be needed. My math skills are what a normal (in a statistical sense, not on a scale of sanity) education would give, but thankfully most of the course was approachable. More linear algebra would certainly have helped though. Also not to say all the lectures were easily understandable, some certainly went over my head. The problems require work, though they are doable (or at least most are. As I said, it's only a B). 

So here is the overall impression, I learned a great deal, had a lot of fun working it out, and it was a wonderful experience (and for me, the best part) to watch these distinguished scholars so visibly in love with their subject. And lest anyone be inclined to question the claim about fun above, I offer this picture

[Yours truly trying to figure out the rotation axis on the Bloch sphere corresponding to Hadamard gate using an orange]

A stitch in time

A stitch in time, saves nine, they say. To really appreciate its meaning, one needs to have a root canal performed though.

Take good care of your teeth.

Notes from a math lecture

Public lectures have a distinguished history going at least as far back as Faraday, but I hardly have any history of attending them. Call it new year fervor that has not subsided yet (or whatever), something did prompt me out of my laziness when I came to know of a public lecture to be given by Prof. Schmid from Harvard last week. My thinking was, more or less, it's a public lecture, How hard can it be?

The topic of the lecture was 'Riemann's continuous, nowhere differentiable function'. As it happens, before Riemann it was thought that a function that is continuous everywhere but differentiable almost nowhere could not exist. Weierstrass was the first to publish such a function, though Riemann (second hand reports claim) gave an example of such a function earlier, but without giving proof. Working that out took a while. G. H. Hardy showed in 1916 that the function is not differentiable at irrational points, while Gerver and Smith showed in 1970s that it is not differentiable at rational points either, except those of the form p/q with p and q relatively prime. Prof. Schmid worked on this function himself, which is intimately related to fractals, a topic which came to prominence much later. The area is important and broad enough to have its own book.

That is the summary, and I am afraid I cannot go in more detail. The lecture was obviously intended for students who are learning related stuff and was full of details and formalism, though the key ideas (like the ones mentioned above) were clearly  brought out. I remember reading John Derbyshire's Prime obsession with great interest, and those who have read it (or are otherwise familiar with the history of Riemann hypothesis) would not fail to notice a parallel here. One minor quibble on the personal front is that I was interested in getting a view on, of the six remaining millennium problems (which include both Riemann hypothesis and P vs NP), which one we are closest to solving, but ended up squandering the opportunity to ask. 

Overall it was a good learning experience, and sitting in a hall surrounded by an overwhelmingly young crowd brought back memories of my own college days, turning it into a refreshing one as well.

First few days with Pixel2

This is not a systematic review of Pixel2. Many of those exist, and in any case, interest in such a thing would be low because Pixel2 is not that new anymore. Instead, what follows is a bunch of impressions, in no particular order. Note that my previous phone was the first gen Moto G. While an excellent phone when I bought it, over time it grew many warts, making me spend a lot of energy in cursing (being able to curse in three languages was a boon here). Undoubtedly my impressions are tinged by that experience.

The first thing I noticed after opening the box is, it's light. Cross that, it is surprisingly light.

It charges fast, but also seems to discharge fast, especially when data network is in use.

The backside gets a bit warm with extensive use.

This was the first time I really used a voice interface, and I continue to be astounded by the accuracy of Google assistant. I find it quite uncanny too, e.g. the first time I asked it to play a song, it came up with ye jo des hai tera from Swades.

Much has been said about its camera, so I'll just mention that I have replaced an iPhone owner as the chief photographer at office birthdays.

I don't have a VR headset yet, but did use it once on a relative's Pixel2. The roller-coaster demo gave me a very real dizziness.

I had pretty much stopped trying new apps, and the ones I used formed a close-to-immutable set. Now I am (much more) likely to be found with my head buried in the phone. 

I restarted using Twitter, and (as evidenced by this post) am more likely to blog. I check Facebook more often, and the same applies (probably to a larger degree) to Quora, Stackoverflow, HN, LinkedIn, Medium, TechCrunch and more.  Which brings me to the next point.

Information overload was already a problem, and it grows worse with a better phone. Same goes for the distraction angle. Thankfully relief (so to speak) is not far away; the play store has a number of Meditation apps too :-) So Headspace joins my trusty Insight timer  (but I am yet to try it, being busy writing this post).

The EMI is pretty high (had to say it)! :-p