LOG#178. Divergent sums: The Number awakens!

Are you divergent? Divergences are usually sums or results you would consider “infinite” or “ill-defined” (unexistent) in normal terms. But don’t be afraid. You can learn to “regularize” a divergent series or sum. Really? Oh, yes!Beyond faction of a well-known … Continue reading


Joël Scherk (not Schrek, the ogre) was a French theoretical physicist with a tragic death. Perhaps his contributions were short, but they were important in the fields of supersymmetry (SUSY), supergravity (SUGRA) and superstrings. Moreover, he also introduced some crazy … Continue reading

LOG#176. The cosmological integral.

Hi, there! In this short note I am going to introduce you into a big problem from a simple integral I use to call “the cosmological integral” (it should be the cosmological energy density integral, but it is too long…). … Continue reading

LOG#175. BH and Saint Seiya: Infinite Break and beyond!

  This post contains some exercises and challenges for you. In fact, crazy me, I used some of them for my classroom usage (just a fun way to survive is to design and propose maniac ultrageek problems to your students, … Continue reading

LOG#174. Basic black hole physics.

In this year, 2015, we celebrate the Light Of Year (LOY) and one century of general relativity (GR), a misnomer for something that should be called relativistic theory of gravity. Let me celebrate the centenary of general relativity with some … Continue reading

LOG#173. Proton decay.

Are diamonds and other (crystalline) jewels/gemstones forever? Well, if protons are stable they are. If not, you are lost! We are all lost indeed in such a case…(However, I am sure that Superman would be fine to know the fact … Continue reading

LOG#172. Higgscelebration: 3 years of a Higgs-like boson!

In 2012, July 4th…We had the Higgsdependence day! A SM Higgs-like resonance was discovered at the LHC and was announced to the world. Today, we celebrate this discovery of the Higgs-like thing or particle almost 3 years ago. So let … Continue reading

LOG#171. From Bohrlogy to dualities.

Old (old fashioned!) Quantum Mechanics is understood as the quantum theory before its final formulation around 1927-1931…It includes the Bohr model, the Wilson-Bohr-Sommerfeld quantization and some other tricks like the one to take into account the finite nuclear size. For … Continue reading

LOG#170. The shortest papers ever: the list.

Hi, everyone. In this short post I am going to discuss some of the shortest papers ever written all over the world!!!!! This idea came to my mind due to a post by @seanmcarroll on twitter and other social networks… … Continue reading

LOG#169. A two level problem.

This post is the solution of the following problem: pick an atom with two energy levels. They have a transition wavelength of 580nm. At room temperature are in the lower state. 1) How many atoms are in the upper state, … Continue reading