The Quote Of The Week - Pati On Preons

Jan 24 2014 | 3 comment(s)

"The most important task at hand is experimental. Based on our considerations of dynamical symmetry breaking through preons and the assumption of universal size for all quarks and leptons, we are led to predict that quarks and leptons have an inverse size of the order of 2-3 TeV. This can be tested by high-luminosity 5-10 TeV machines in the near future by looking for form factors for quarks and leptons and for excess production of lepton pairs in pp or ppbar collisions."

Jogesh Pati, "Preons and their implications for the next-generation accelerators", Proceedings of  the third annual workshop of the ICTP Summer Workshop on Particle Physics, Trieste 1983, p. 399-459.

Jan 23 2014 | 17 comment(s)

I must say I feel proud of myself tonight.

In Italy a unified procedure to rank candidates to the position of associate or full professor has been launched last year, and I of course participated to the qualification by sending a documentation of the work I performed and the articles I wrote in the course of my scientific career. With me, thousands of other candidates did the same.

Note that as a researcher for the Italian Institute of Nuclear Physics (INFN) I am presently following a career parallel to the one existing in the University. Despite that, in Italy everybody knows that titles such as the one granted by the selection mentioned above are important for one's career.

Now We Can See If That Cat Is Alive Or Dead: Peeking Inside Schrodinger's Box

Jan 20 2014 | 3 comment(s)

Measuring a 27-dimensional quantum state is a time-consuming, multistage process using a technique called quantum tomography, which is similar to creating a 3D image from many 2D ones.

Researchers have instead been able to apply direct measurement to do this in a single experiment with no post-processing. In a new paper they demonstrate direct measurements of the quantum state associated with the orbital-angular momentum.

The Quote Of The Week

Jan 20 2014 | 0 comment(s)

"Statistical power does not corrupt"

Leland Wilkinson, "Statistical Methods in Psychology Journals", in American Psychologist, August 1999.

[Note: "power" in the context of statistical tests measures the probability that a test rejects the null hypothesis when the alternate hypothesis is true). Thanks to Michael Schmitt for pointing out the quote]

Are Tetraquarks Real ?

Jan 18 2014 | 8 comment(s)

Tetraquarks are hypothetical particles made up by four quarks (two quarks and two antiquarks). Unlike mesons (quark-antiquark pairs) and baryons (three-quark or three-antiquark systems), the quarks in a tetraquark are quite loosely bound within their confinement volume by strong interactions, as can be calculated with the help of quantum chromodynamics. Their tendence to separate into two quark-antiquark systems should yield a very short lifetime, making their observation quite difficult. However, some tentative evidence for their existence exists.

One more view at Italy's escape of brains

Jan 15 2014 | 15 comment(s)

In Italy the debate over the escape of brilliant young scientists to foreign countries has been going on for decades now. Italians like to debate, much less to solve their own problems. So although the problem is clearly identified and a recipe to solve it is evident, nobody does anything to implement the solution. Which, of course, would be to raise salaries to researchers and allow for quicker and easier ways to access a career for young post-docs.

Newtonian Gravity with a Tiny Test Mass

Jan 10 2014 | 27 comment(s)

I will try to keep my Newtonian wig on. Digressions will be in well-defined sidebars. Time to serve the meat and potatoes.

The Action for the Newtonian Gravitational Field

Two things go into this action: a mass density and a scalar field:

\begin{align*} S_{_{NGF}}&= \int \mathcal{L}(\Phi, \nabla \Phi)\\ &= \int d^4 x \left(-\rho\, \Phi - \frac{c^2}{2 G} (\nabla \Phi)^2\right ) \end{align*}

Fusion: Now With Less Instability, Thanks To A 19th Century Technique

Jan 10 2014 | 0 comment(s)

The Z machine at Sandia National Laboratories is moving us toward a fusion future by stepping into the past - in this case using a 19th century device called a Helmholz coil, which is a pair of circular coils on a common axis with equal currents flowing in the same sense and that produces a nearly uniform magnetic field when electrified.

In recent experiments, two Helmholz coils, installed to provide a secondary magnetic field to Z's huge one, unexpectedly altered and slowed the growth of magneto-Rayleigh-Taylor instabilities, an unavoidable, game-ending plasma distortion that usually spins quickly out of control and has sunk past efforts to achieve controlled fusion.

The Universe: Now Measured To 1 Percent Accuracy

Jan 09 2014 | 4 comment(s)

Today the Baryon Oscillation Spectroscopic Survey (BOSS) Collaboration announced that they have measured the scale of the universe to an accuracy of one percent.

The Quote Of The Week - The Nonsensical Hypothesis Of Quarks

Jan 09 2014 | 2 comment(s)

At the 1962 Rochester conference in Geneva, the prediction that a particle later called the Omega minus should exist, already proposed in a paper by Glashow and Sakurai, was not considered important enough to be mentioned in any invited or contributed talk. It was mentioned in a comment from the floor by Gell-Mann. The paper proposing the existence of quarks was accepted by Physics Letters only because it had Gell-Mann's name on it. The editor said, "The paper looks crazy, but if I accept it and it is nonsense, everyone will blame Gell-Mann and not Physics Letters. If I reject it and it turns out to be right, I will be ridiculed."

Harry Lipkin, "Quark Models and Quark Phenomenology", in "The Rise of the Standard Model", Cambridge UP 1997