Maxwell’s Demon, Boltzmann’s H theorem, Ergodicity and other awesome stuff

I just discovered this treasure trove on the foundations and history of statistical mechanics:

Compendium of the foundations of classical statistical physics, by Jos Uffink (PDF)

The abstract:

Roughly speaking, classical statistical physics is the branch of theoretical physics that aims to account for the thermal behaviour of macroscopic bodies in terms of a classical mechanical model of their microscopic constituents, with the help of probabilistic assumptions. In the last century and a half, a fair number of approaches have been developed to meet this aim. This study of their foundations assesses their coherence and analyzes the motivations for their basic assumptions, and the interpretations of their central concepts. The most outstanding foundational problems are the explanation of time-asymmetry in thermal behaviour, the relative autonomy of thermal phenomena from their microscopic underpinning, and the meaning of probability.

A more or less historic survey is given of the work of Maxwell, Boltzmann and Gibbs in statis- tical physics, and the problems and objections to which their work gave rise. Next, we review some modern approaches to (i) equilibrium statistical mechanics, such as ergodic theory and the theory of the thermodynamic limit; and to (ii) non-equilibrium statistical mechanics as provided by Lanford’s work on the Boltzmann equation, the so-called Bogolyubov-Born-Green-Kirkwood-Yvon approach, and stochastic approaches such as ‘coarse-graining’ and the ‘open systems’ approach. In all cases, we focus on the subtle interplay between probabilistic assumptions, dynamical assumptions, initial conditions and other ingredients used in these approaches.

This will keep me busy.

The Walking Dead’s Bloody Mess

There are spoilers below. You’ve been warned. If you are even further behind watching The Walking Dead – Season 2 than me and can’t bear the thought of being spared the waste of those hours of your life, this is not for you.

I have recently started catching up on The Walking Dead – Season 2. At the end of Episode 1, Carl Grimes, son of our hero, Rick Grimes, is wounded in a hunting accident. Episode 2 is then devoted to keeping Carl from bleeding out. This means surgery and blood transfusions. Unfortunately, you can’t just stick blood from one person into someone else1. The immune system will attack a blood transfusion as a foreign invader if the donated blood is not compatible with the recipient. These reactions can be fatal. Keeping blood banks stocked is difficult in our modern world. Trying to find appropriate blood donors for a kid with internal bleeding in a zombie-filled, post-apocalyptic wasteland poses a particular challenge. Continue reading “The Walking Dead’s Bloody Mess”

Wikipedia fail #208 – on the origins of enthalpy

Admit it, we all have a love-hate relationship with Wikipedia, as we do with anything that is both useful and frustrating, which seems to include just about anything related to the internet.

Here is yet another instance where the weaknesses of Wikipedia’s crowd-sourcing comes to the fore: enthalpy. Under the subheading ‘Origins’, we first encounter two sentences explaining the Greek roots of the word, when one sentence would have been sufficient. Next, we read three sentences explaining that the origins of the concept are often misattributed Clapeyron and Clausius. Five sentences later, in the second paragraph, we finally read something about the origin of the concept of enthalpy (but the emphasis still inappropriately remains on the origin of the word and not the concept).

Wikipedia’s biggest weakness is not inaccuracy, but lack of a filter and a proper sense of emphasis, which is why the articles often read like they’ve been written by high school students. Of course that doesn’t stop me from reading Wikipedia 20 times a day.

Hunger Games and Teenage Angst in the New Yorker

I read this one when it came out back in 2010, but The New Yorker is highlighting it today to capitalize on the Hunger Games movie release:

“Fresh Hell”, Laura Miller:

…dystopian stories for adults and children have essentially the same purpose—to warn us about the dangers of some current trend. That’s certainly true of books like “1984” and “Brave New World”; they detail the consequences of political authoritarianism and feckless hedonism. This is what will happen if we don’t turn back now, they scold, and scolding makes sense when your readers have a shot at getting their hands on the wheel. Continue reading “Hunger Games and Teenage Angst in the New Yorker”

Science career pessimism: it’s not just me

Before actually becoming a scientist, I had a particular view of what a science career was about. Part of this view came from reading biographies of famous scientists, but a big part came from being the child of scientist who is not famous but very successful. My experiences in grad school and during my postdoc have been a great disillusionment, despite the marvelous intellectual experiences and the caring and inspiring mentors it’s been my privilege to work with. You’re probably thinking, well duh, anyone in any career hits a point of disillusionment because nothing is every as glamorous as it seems from the outside, except perhaps the life of a billionaire hedge fund manager. (If you make more than $100 million annually, I don’t want to hear any shit about your life not being as glamorous as it seems… it’s plenty glamorous.)

Back to science careers – as I’ve discussed before, there is some external evidence that my impressions aren’t simply the natural impatience of someone near the end of the long so-called training period. Here’s one more report on the issue, this time from way back in 2001, when the NIH budget was still on a path to doubling and long before R01 grant success rates hit an all-time low in 2011:

“Careers and Rewards in Bio Sciences: the disconnect between scientific progress and career progression” (PDF): Continue reading “Science career pessimism: it’s not just me”