2022 tweets

Jan 17, 2022

"I want you to have a book that is 8.5x11, but that has this 7-foot area rug... so you then have the satisfaction of lying on the floor with this book, because there's no other way to read it, and transporting yourself, getting yourself into it." youtube.com/watch?v=Nbmnx0…

Jan 18, 2022

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"the unreasonable effectiveness of unrealistic simplifications" (Ziman / Dill & Bromberg)

3. JELLIUM
It is typical of modern physicists that they will erect skyscrapers of theory upon the slender foundations of outrageously simplified models. We have an array of ions, each with charge enough to bind an electron if left to itself, and an equal number of electrons which seem to be able to move around a bit amongst the ions. So we take the bit between our teeth, and assume that the ions are not there at all! Or, rather we smear them out into a fixed uniform background of positive charge—a sort of jelly—in which the electrons move quite freely. We need this jelly to make our system electrically neutral, so that the electrons will not be driven explosively apart by their coulomb repulsion. It is sometimes instructive to think about the effects of elastic waves in this medium, but generally speaking it can be ignored. Thus the properties of ¿ellium are those of a free electron gas.
On the face of it this model seems wildly unrealistic. How can we simply ignore those strong local forces, varying so rapidly in the neighbourhood of each ion? In Part III we shall see that it is a much better representation of the metal than one would have thought at first.

Models are mental toys to guide our thinking. The most important ingredients in a good model are predictive power and insight into the causes of the predicted behavior. The more rigorous a model, the less room for ambiguity. But models don't need to be complicated to be useful. Many of the key insights in statistical mechanics have come from simplifications that may seem unrealistic at first glance: particles represented as perfect spheres with atomic detail left out, neglecting the presence of other particles, using crystal-like lattices of particles in liquids and polymers, and modeling polymer chains as random flights, etc. To borrow a quote, statistical thermodynamics has a history of what might be called the unreasonable effectiveness of unrealistic simplifications. Perhaps the classic example is the two- dimensional Ising model of magnets as two types of arrows, up spins or down spins, on square lattices. Lars Onsager's famous solution to this highly simplified model was a major contribution to the modern revolution in our understanding of phase transitions and critical phenomena.

Jan 30, 2022

web.archive.org/web/2019030316…

It is alarming that so many Nobel Prize recipients have lamented that they would never have survived this current academic environment. What are the implications of this on the discovery of future scientific paradigm shifts and scientific inquiry in general? I asked Professor Brenner to elaborate.
SB: He wouldn't have survived. Even God wouldn't get a grant today because somebody on the committee would say, oh those were very interesting experiments (creating the universe), but they've never been repeated. And then someone else would say, yes and he did it a long time ago, what's he done recently? And a third would say, to top it all, he published it all in an un-refereed journal (The Bible).

Feb 6, 2022

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