In a paper posted to the arXiv a few days ago Stephen W. Hawking the preeminent expert on black holes argued quite effectively that given what we know about quantum gravity they don't exist. Quantum theory allows for matter and energy to escape from a black hole albeit very slowly, and scrambled up. In fact this process has been known for a very long time and is named "Hawking radiation".
"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.
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.
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.
"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]
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.
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.
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:
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.
Today the Baryon Oscillation Spectroscopic Survey (BOSS) Collaboration announced that they have measured the scale of the universe to an accuracy of one percent.