Physics

Being still confined in a rather long vacation (now in the Italian eastern alps), my blogging power is limited. I will just offer you some thoughts on a fundamental parameter of the Standard Model called "W boson width". The W boson, like any unstable subatomic particle, has a very short lifetime, which depends on the strength of its couplings to lighter particles, on its own mass (generally the heavier a particle is, the faster is its disintegration), and on the availability of lighter bodies into which to decay without breaking any fundamental rule. In the case of the W, the mass is quite…

Welcome to my first blog entry ever! That the Big Bang is the start of the universe, the mysterious “point of creation”, is stated often still today, even by prominent physicists. It is also not true. The Big Bang is what you get when you back-extrapolate the today visible expansion of the universe into the past. One gets to the point where there is the so called “reheating” after inflation. The result of reheating is the Big Bang, a hot and dense state for sure, but it is not thought to be the beginning anymore. The Big Bang is a set of conditions of an extremely hot, dense, expanding…

The redefiner Ɽt can be mimicked by a trail of infinitesimal unitary transforms. Each subsequent trail element has eigenvectors that differ from those of its predecessor. These eigenvectors are also eigenvectors of Ɽt. For a single vector, which is not an eigenvector of Ɽt, the action of Ɽt can be represented by the integrated activity of this trail on that vector. This can be interpreted as the activity of a genuine unitary transform Ut. When a redefiner Ɽt is applied to the eigenvector |q> of an operator Q with eigenvalue q, then the eigenvector is transferred into another vector |Ut q…

W bosons have been thoroughly studied at the Tevatron collider. Discovered by the UA1 experiment at the CERN SppS proton-antiproton collider in 1984, these particles have since been produced also in electron-positron collisions at LEP II (in pairs), and recently at the Large Hadron Collider. But the CDF and DZERO experiments have some of the most precise measurements of the physics of these particles, thanks to their now very large datasets. A question that has always caused headaches in experimentalists and theorists concerning W production is how large a fraction of these particles is…

A new type of operator is required. Why? Because unitary transformations cannot move subspaces of a Hilbert space. They cannot move their own eigenvectors. Since their eigenfunctions span the whole Hilbert space will every subspace of dimension higher than one contain one or more eigenfunctions of every unitary transformation. Subspaces that represent objects must be moveable in order to implement the dynamics of those objects. Unitary transformations can only move one-dimensional subspaces. However, the single vector contained in a one-dimensional vector cannot carry on its own all the…

I almost categorized this under Humor but it's more scary than funny... TPM highlights the Conservapedia argument against the theory of relativity: "The theory of relativity is a mathematical system that allows no exceptions. It is heavily promoted by liberals who like its encouragement of relativism and its tendency to mislead people in how they view the world. ... Virtually no one who is taught and believes relativity continues to read the Bible, a book that outsells New York Times bestsellers by a hundred-fold." Check out the piece in New Scientist to find out how the crazies link Obama,…

A multiplet is a simple thing to describe: it is a collection of several identical or nearly identical things. Here, however, a difficulty arises because a "multiplet" is a manifestation of symmetry groups, and symmetry groups are tough objects to discuss. So if in a scientific paper you write "the new hadron might belong to a SU(3) multiplet", you have the additional trouble that you need to avoid discussing group theory to an unwilling listener. What is SU(3) ? Do we actually care? Thus wrote Tommaso Dorigo in The Language Barrier on 26th May this year. Well I for one do care.  I have…

CDF and DZERO, the two experiments at the Fermillab Tevatron collider, have studied top quark production since their own discovery of the heavy particle in 1995 (see here, here, and here for a three-post history of the top quark quest). As the number of produced proton-antiproton collisions kept increasing since 2002, the number and depth of studies performed in top-quark production events have similarly furthered our understanding of the fascinating physics of the heaviest known elementary particle. Top quarks are produced by the energetic interaction of a quark and an antiquark, or a pair…

In the It-From-Bit series I have reported extensively on Verlinde's 'entropic gravity' concept. I have also provided you with an illustrative 'mikado universe' picture of entropic gravity. This got topped off with my own intuitive notion that in an entropic universe, not only gravity, but also accelerated cosmic expansion emerges. As a result, in one fell swoop, entropy eliminates the need for a fundamental force of gravity as well as the need for dark energy.  All of this can be summarized succinctly by expanding on an analogy put forward by Dennis Overbye in the New York Times: There…

When thinking of M theory and how it's popularized so much is said about it's wild and wonderful predictions.  However their is not much said about how to think of the M branes themselves.  I was at the beach today and thought as I was looking at the water of M theory.  The surface tension is much like an Mtheory Brane.  The little waves and ripples in the surface are analogous to the ripples on lake Michigan.   I thought about cutting the video up , dubbing in cleaner audio but really is this that serious?  Enjoy