In my last blog, I wrote in detail about zero, one, real numbers, complex numbers and quaternions (or as I now prefer to call them, space-time numbers although I use them interchangeably). For each sort of number, there were rules for addition, rules for multiplication, and a relevant animation. The rules happened to get more complicated going from zero out to the space-time numbers, but they were all of the same form. That makes sense since zero, one, the real numbers, and the complex numbers live inside the tent of space-time numbers.

This week I am in Warsaw, where I attend the XI workshop on particle correlations and femtoscopy. I am actually here to give a seminar on statistical methods in particle physics next Thursday, but of course I am also going to try and deepen my understanding of the field of investigations of heavy ion collisions.

Jan Pluta, one of the old-schoolers of the field, gave an introductory talk this morning. It was titled "A brief history of femtoscopy and particle correlations - a personal view". I am reporting below some impressions from his presentation.

What is femtoscopy ? Jan started by warning that he would indeed only give a personal view of the history of the field, and that the view of others may be very different.
If you are into Nuclear Physics there is very good chance you know about nuclear electromagnetic moments. Actually, nuclear electromagnetic moments has been the field of my specialty from the beginning of my scientific career. This is also why my blog in was named "Moment Zero" and not because there was some zero-time singularity I broke into writing about scientific stuff (not that I have been very active in here either!). The term nuclear electromagnetic moments 90% of the time refer to the magnetic dipole and the electric quadrupole moment. Each of these physics observables have something important to say about the nucleus.

Is there a battle between astrology and science?

The law of gravity is readily recognized and easily tested.  The force that gave rise to the expression, "whatever goes up must come down" has indeed undergone extensive scientific testing and is largely considered to be one of the most fundamental forces in all of nature.  The very pull of it can be felt as you read these words as you are held to your chair or the floor rather than floating around like a helium balloon.  Given this, is it possible for the gravitational forces from the planets to give rise to meaningful predictions from astrology?

Recurrently, uninformed journalists re-discover the h-index and decide to create their own list of the "top scientists" in their country. The most zealous also draw some summary statistics from the list, and then venture to speculate wildly about it. Alas, it's a pattern I've seen a few times now.

The latest is an article which somebody posted on my Facebook column. It is uninteresting to see what conclusions are drawn from the graphs and lists published there, as the data are quite incomplete - in the h-index-ordered list of Italian researchers I do not appear, for one, but similarly do not dozens of top scientists who have even higher h-indices.

As I am spending my time these days selecting candidates for early-stage researcher positions in the EU network I am coordinating, I am reminded of my own experience as a participant to job interviews from the other side of the table. The text below tells the story of my interviews for a post-doctoral position in 1998. Enjoy! 


Discovering possible new forces in nature is no easy task. To discover the secret of gravity, the public thinks it took an apple falling from a tree, but really it took him inventing Calculus. linked to Newton's arguably apocryphal apple experiment has remained anchored in popular culture.

In January 1986, Ephraim Fischbach, Physics Professor from Purdue University in West Lafayette, Indiana, claimed the hypothetical possibility of the existence of a fifth force in the universe and it has spurred a tremendous amount of research in gravitational physics even though its existence, as initially formulated, has not been confirmed by experiment.

  Nonlocality is an inherent natural feature of quantum reality described by its wave function (WF). It shows itself up not only in the widely discussed cases with two or more particles, but also with one spinless particle. The point is that the WF-Collapse (WF-C) is in general a nonlocal phenomenon. Consider for example a one particle plane wave in quantum mechanics: the particle location in one place is a WF-C that replaces the plane wave by a new WF with zero location in all other places. It means simultaneous prediction with confidence of negative search results at any other remote place where the particle could have been detected before the WF-collapse. It is not spooky; it is strange, but natural.   
A longtime follower of this blog, Tony Smith, pointed out to me today this arxiv paper published three days ago. In it, CMS data from Run 1 of the LHC are used to speculate that there might be a second Higgs boson hiding in the data at a mass of about 145 GeV. Check out the two graphs that they produce.
The first one, shown below, is their own interpretation of the four-lepton invariant mass from CMS data and background in the H-->ZZ--> four lepton final state:

Yesterday my 16 year old son surprised me by explaining that he had been taught at school what alpha, beta, and gamma decays are. He had learned a lot, but I was able to add a little more background information to the picture as he asked me what was the neutrino, which his professor had correctly explained was one of the particles emitted in beta decay.

With hindsight, my surprise probably comes from keeping my brain inactive and sticking to a rather conservative idea of how sciences should be taught at school; that idea is that understanding physics requires you to have some solid basis in maths, and that the explanation of phenomena should proceed along with quantitative calculations.