A collection of interesting posts from physics blogsphere :

Short Distances: Newton Still the Man (from Cosmic Variance by Sean)

Via Chad Orzel, I see that the latest constraints on short-distance modifications of Newton’s inverse-square law from the Eot-Wash group at the University of Washington have now appeared in PRL. And the answer is: extra dimensions must be smaller than 0.045 millimeters (in any not-too-contrived model)…


Undergraduate Theory Institute(from Cosmic Variance by Sean)

Sadly, I’m not here to announce that applications are now being accepted for students who would like to participate in this year’s Undergraduate Theory Institute. That’s because there is no such thing as the Undergraduate Theory Institute, at least as far as I know. (Google doesn’t know of one either.) But I think it would be a great idea — maybe if I post it here on the blog someone will start it.

It’s increasingly common for physics students to participate in some kind of research during their undergraduate years. The NSF has a very successful Research Experience for Undergraduates program, for example, that funds students to do summer research, typically at an institution other than their own. Getting involved in research as early as possible is a great idea for students, for a number of reasons. Most importantly, the flavor of doing real research, where the answers aren’t in the back of the book, is utterly different from almost any classroom experience or even self-study, where you are trying to learn material that someone else has already mastered. The move from following a course of study to striking out into the unknown is one of the hardest transitions to make during graduate school, and getting a head start is an enormous help. On a more prosaic level, it’s useful to work closely with an advisor who can end up writing letters of recommendation. And let’s not forget that it can be a lot of fun!..

Dancing Ball Lightnings in the Lab (from Backreaction Blog)

Ball lightnings are mysterious things: Small, bright balls of fire suddenly appear during a thunderstorm, swirl around, make sometimes funny noises, and leave behind a smell of ozone…

Since ball lightnings are not only spooky, but also very elusive, there has been a lot of speculation how to understand and explain them in a scientific way: People have suggested that it may be some ionised balls of plasma held together by their own magnetic fields, or even such exotic things as mini black holes leftover from the big bang…

A more “down to Earth” explanation was proposed in a 1999 Letter to Nature:..

From Griffiths to Peskin: a lit review for beginners (From “An American Physics Student in England” )

a.k.a. “How to get started learning QFT as an undergraduate.”

Quantum Field Theory (QFT) plays a key role in all branches of theoretical physics. For students interested in high energy theory, exposure to QFT at any early stage is slowly becoming the standard for top American graduate schools. This is already the case for the Mathematics Tripos at Cambridge…

An inspired student with adequate background should be able to take quantum mechanics in his/her second or third year and then progress directly to a ‘real’ QFT course with a bit preparation, without going through the rigmarole of a year-long graduate quantum mechanics course.

Instead, I present a rough guide to pedagogical QFT literature so that a motivated student can prepare for a graduate-level QFT course or a get started with a self-study during the summer after his/her undergraduate quantum mechanics course. As a someone who was in this position in the not-too-distant-past, I hope some personal experience with the pros and pitfalls of the listed texts will be helpful for other other students interested in doing the same….

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