Another fruitful week has passed and it seems like a good time to have a look at the top news of physics. As always, here are three top news stories summarized below. If you would like to receive these news straight to your email box, register for our email newsletter.
As expected, not every scientists thinks that it’s time to celebrate the revolutionary results from the BICEP2 project. Theoretical physicists and cosmologists James Dent, Lawrence Krauss, and Harsh Mathur have submitted a brief paper (arXiv link) stating that, while groundbreaking, the BICEP2 Collaboration findings have yet to rule out all possible non-inflation sources of the observed B-mode polarization patterns.
“However, while there is little doubt that inflation at the Grand Unified Scale is the best motivated source of such primordial waves, it is important to demonstrate that other possible sources cannot account for the current BICEP2 data before definitely claiming Inflation has been proved,” explained Dent, Krauss, and Mathur in their recent paper.
95 % of the universe is a mystery
Quintessence and phantom fields, two hypotheses formulated using data from satellites, such as Planck and WMAP, are among the many theories that try to explain the nature of dark energy. Now researchers from Barcelona and Athens suggest that both possibilities are only a mirage in the observations and it is the quantum vacuum which could be behind this energy that moves our universe.
There are numerous models aiming to explain dark energy. One possibility is the presence of an energy or phantom field whose density increases with time, causing an exponential cosmic acceleration. Another possibility is the existence of quintessence, an invisible gravitating agent that instead of attracting, repels and accelerates the expansion of the cosmos. From the Classical World until the Middle Ages, this term has referred to the ether or fifth element of nature, together with earth, fire, water and air.
Now researchers from the University of Barcelona (Spain) and the Academy of Athens (Greece) have used the same satellite data to demonstrate that the behaviour of dark energy does not need to resort to either quintessence or phantom energy in order to be explained. Find out more using the link in the title.
Commercial silicon-based solar cells – such as those seen on the roofs of houses across the country – operate at about 20% efficiency, however, to reach this level of efficiency, over 20 years of research were needed. Recently, a relatively new type of solar cell based on a perovskite material has been pioneered by an Oxford research team led by Professor Henry Snaith. Perovskite solar cells, the source of huge excitement in the research community, already lie just a fraction behind commercial silicon, having reached a remarkable 17% efficiency in only two years time. Another great thing about these cells is that they can also be used to produce cheap lasers.
“This first demonstration of lasing in these cheap solution-processed semiconductors opens up a range of new applications,” said lead author Dr Felix Deschler of the Cavendish Laboratory. “Our findings demonstrate potential uses for this material in telecommunications and for light emitting devices.”