Physics

I am spending the week in the pleasant resort of La Biodola, in the Elba island. Elba is a beautiful island just off the coast of Tuscany. Here Napoleon was exiled after his abdication in 1814 (he arrived here on May 30th). Exactly 200 years later, 100 Italian researchers have decided to exile themselves here to discuss the future 10 years of accelerator-based experiments, to understand where to "put their money", or better their research activities and efforts.
The laws of physics are absolute - in theory.  And with an exception. So absolute doesn't always mean what we think it means.

How heat and temperature related to energy, the laws of thermodynamics, seem to violate the laws of physics theoretically. But now they theoretically don't.

A paper recently published in EPJ B discussed a theoretical model of the environment's influence on a particle does not violate the third law of thermodynamics, despite appearances to the contrary. These findings are relevant for systems at the micro or nanometer scale that are difficult to decouple from the heat or the quantum effects exerted by their environment.

Some Sun-like stars are 'earth-eaters.' During their development they ingest large amounts of the rocky material from which 'terrestrial' planets like Earth, Mars and Venus are made.

Trey Mack, a graduate student in astronomy at Vanderbilt University, has developed a model that estimates the effect that such a diet has on a star's chemical composition and has used it to analyze a pair of twin stars which both have their own planets.


I came to know through a social network (I have many colleagues as friends there, and they usually post more useful stuff than cute kittens) that ATLAS has launched a very intriguing competition. One you can participate to, if you have some programming skills; no knowledge of particle physics is needed.

The idea is to ask you to classify as signal (Higgs decay to tau lepton pairs, if you really want to know!) or background (anything that looks similar to it but involves no Higgs boson) a set of 550,000 events, for each of which ATLAS gives you 30 kinematical quantities measured in the detector (it is a simulation, but it's a pretty good approximation of reality).

Physicists say they have discovered how to create matter from light - a feat thought impossible when the idea was first theorized 80 years ago. There is just one problem. In order to test the newest hypothesis, a new& machine would have to be built.

In just one day over several cups of coffee in a tiny office at Imperial College London, three physicists believe they worked out a relatively simple way to physically prove a theory first devised by scientists Breit and Wheeler in 1934. Yes, they solved a puzzle that has eluded the rest of the world in an afternoon. Well, on paper.


In this blog, I will review my thoughts on the action of general relativity, how it is used for the field equations and equations of motion.  There is much to consider, so perhaps this will create a means for discussing this deep subject.




The Action

Two months after the controversial BICEP2 announcement, The Washington Post writes « Big Bang backlash: BICEP2 discovery of gravity waves questioned by cosmologists » and National Geographic emphasizes « Big Bang Discovery Comes Under Fire.

"Subatomic particles act in quantum ways—they have a wave-like nature—and so can atoms, and so can whole molecules since they're collections of atoms," Schwab says. "So the question then is: Can you make bigger and bigger objects behave in these weird wave-like ways? Why not? Right now we're just trying to figure out where the boundary of quantum physics is," says Keith Schwab, Professor of Applied Physics at Caltech. 

And that means finding a way to make measurements that go beyond the limits of quantum physics.


I receive much crackpot email. There is a very common misunderstanding often central, one I have not seen a good answer to anywhere. This is partially due to that few who write about physics counter crackpot theories well. Allow me to explain this point with a new personal story before explaining why energy seems quantized, why photons seem to be little packets of energy rather than a concept that describes quantum interactions more or less well.

Very recently, a combination of the precise measurements of the mass of the top quark obtained by the CDF and DZERO experiments at the Fermilab Tevatron collider with those produced by the ATLAS and CMS experiments at the CERN LHC collider has been produced, obtaining a result of 173.34 GeV, which surprised nobody -of course- with a very small total error bar: 0.76 GeV, a mere 760 MeV, not even a proton's mass.