Physics


Time-dependent Maxwell's equations in media 

By Robyn Arianrhod, Monash University

It’s hard to imagine life without mobile phones, radio and television. Yet the discovery of the electromagnetic waves that underpin such technologies grew out of an abstract theory that’s 150 years old.

Can a penalty kick simultaneously score a goal and miss?

In the realm of quantum mechanics that is certainly be true, because microscopic objects can take different paths at the same time.  Almost 100 years ago physicists Werner Heisenberg, Max Born and Erwin Schrödinger created this new field of physics which would be called quantum mechanics. Objects of the quantum world, according to quantum theory, no longer move along a single well-defined path. Rather, they can simultaneously take different paths and end up at different places at once. Physicists speak of quantum superposition of different paths.  
The publishing giant Elsevier is about to launch a new journal, Reviews in Physics. This will be a fully open-access, peer-reviewed journal which aims at providing short reviews (15 pages maximum) on physics topics at the forefront of research. The web page of the journal is here, and a screenshot is shown below.

The CMS collaboration has released yesterday results of a search for Majorana neutrinos in dimuon data collected by the CMS detector in 8 TeV proton-proton collisions delivered by the LHC in 2012. If you are short of time and just need an executive summary, here it is: no such thing is seen, unfortunately, and limits are set on the production rate of heavy neutrinos N as a function of their mass. If you have five spare minutes, however, you might be interested in some more detail of the search and its results.

I live in Massachusetts, home of the National Football League team the New England Patriots.  I admit to being a fan, being raised as a Minnesota Viking by two enthusiastic parents.  The Vikings have been to two super bowl 5 times (and lost 5 times, ouch).  Since 1980, I have lived in Massachusetts where the Patriots know how to win the whole thing.  Does that method involve cheating?

A periodic backup of my mobile phone yesterday - mainly pictures and videos - was the occasion to give a look back at things I did and places I visited in 2014, for business and leisure. I thought it would be fun to share some of those pictures with you, with sparse comments. I know, Facebook does this for you automatically, but what does Facebook know of what is meaningful and what isn't ? So here we go.
The first pic was taken at Beaubourg, in Paris - it is a sculpture I absolutely love: "The king plays with the queen" by Max Ernst.



Still in Paris (for a vacation at the beginning of January), the grandiose interior of the Opera de Paris...
Each January, I scamper out of the basement and talk to folks during MIT's Independent Activities Period. The Alumni Association is the sponsor (no one from the physics or math department is inviting me).
This morning I woke up at 6AM, had a shower and breakfast, dressed up, and rushed out in the cold of the fading night to catch a train to Mestre, where my car was parked. From there I drove due north for two hours, to a place in the mountains called Pieve di Cadore. A comfortable ride in normal weather, but this morning the weather was horrible, with an insisting water bombing from above which slowly turned to heavy sleet as I gained altitude. The drive was very unnerving as my car is old and not well equipped for these winter conditions - hydroplaning was frequent. But I made it.
In 1973, during a symposium to celebrate the 500th birthday of Copernicus, Brandon Carter, a post-doctoral researcher in astrophysics at the University of Cambridge, tweaked his audience by stating that humanity did indeed hold a special place in the Universe - the exact opposite of what scientists from Copernicus on have said.

Since then, it has gone in and out of fashion, and the Anthropic Principle, as it was called, was most recently embraced in some M-Theory flavors of string theory.
The CMS Collaboration at the LHC collider has recently measured a non-negligible rate for the fraction of Higgs boson decays into muon-tau pairs, as I reported in this article last summer. The observation is not statistically significant enough to cause an earthquake in the world of high-energy physics, and sceptics like myself just raised a gram of eyebrows at the announcement - oh yeah, just another 2-sigma effect. However, the matter becomes more interesting if there is a theoretical model which allows for the observed effect, AND if the model is not entirely crazy.