Another Sunday is upon us, so, as always, here’s an overview of the top events in the world of physics from this week. To receive these news and other useful stuff straight to your email box, register for our email newsletter.
What if spacetime were a kind of fluid? This is the question that is currently being tackled by physicists working on the theory of quantum gravity. The implication of this is that the structure of spacetime at Planck scale is no longer continuous, just like in a fluid when observing it at sufficient evolution.
Stefano Liberati (SISSA) and Luca Maccione (Ludwig-Maximilian University in Munich) have recently suggested an innovative way of using elementary particle physics and high energy astrophysics to describe the effects that should be observed if spacetime was a fluid. Similar models in the past have suggested changes in the propagation of photons in spacetime, however, the recent work by Liberati and Maccione suggests deeper implications. “If we follow up the analogy with fluids it doesn’t make sense to expect these types of changes only” explains Liberati. “If spacetime is a kind of fluid, then we must also take into account its viscosity and other dissipative effects, which had never been considered in detail.”
Physics can be used to simulate a wide array of situations, including the presidential election
Believe it or not physics has a wide range of applicability in other field, such as sociology, biology and even political science. A great example of this is the research done by a team of physicists working at IFISC in Palma de Mallorca in Spain, who used a computer simulation originally designed to model the transition of iron between magnetized states to create a model to do something similar for voting patterns in the United States.
Needless to say, creating a simulation that would reliably guess the winner of an election is still out of reach. However, the tendency of voters to be impacted by the opinions of others, whether those of people that live near them, or those that commute to places where they work, could be studied and simulated. To model such a complex situation physicists narrowed down the factors of influence to just two: the proportion of Republicans versus Democrats in a given voter’s home county and the proportion of Republicans versus Democrats where they work. Given these assumptions, scientists could then study a variety of situations, the outcomes of which will be compared to the results of the future election.
A solid understanding of the properties of light has been the cornerstone of both classical and modern physics for more than a century. Despite that, we still don’t know everything about light. And the best example of this is a recent discovery by Konstantin Bliokh, who has made a remarkable discovery that a particular type of light known as evanescent waves possesses unexpected dynamical properties. In particular, the momentum and spin of these waves have transverse components that are oriented at right angles to the plane of propagation, which is in sharp contrast with previous knowledge about light.
“Although these extraordinary properties seem to be in contradiction with what is known about photons,” explains Bliokh, “we have shown that they reveal what is known as ‘spin momentum’—an enigmatic quantity that was introduced more than 70 years ago to explain the spin of quantum particles.”