Physics News of the Week: New Methods for Creating Invisibility Cloaks and a Natural Diffraction Grating
Another week has passed and it is time to take a look at what’s going on in the world of science. As always, here’s a summary of the physics news of the week. To receive these news straight to your email, register for our email newsletter.
1. New Map of the Universe May Reconcile Problems in Cosmology (September 11)
Pierre Fleury, Hélѐne Dupuy, and Jean-Philippe Uzan, at the Institut d’Astrophysique de Paris (CNRS) and the Institut de Physique Théorique (CEA), have published a new paper on interpreting cosmological observations by employing different models in a recent issue of Physical Review Letters.
The problem that physicists tackled came from a recent analysis of the results from the Planck experiment. The Planck experiment is investigating the average density of matter and the speed at which galaxies are receding due to the expansion of the Universe. These areas are measured by the matter density parameter and the Hubble parameter, however, the Hubble diagram and the CMB produce two slightly different results for the values of Hubble constant and the matter density. In the new paper, Fleury and colleagues tackle this problem by considering what would happen if they interpreted the supernova observations using a model that describes the Universe as being clumpier. Read the full report here.
2. New Methods for Creating Invisibility Cloaks (September 11)
In the past, the invisibility cloaks were created using metamaterials. Despite positive results, however, metamaterials are expensive and time consuming. Due to this reason, a team of researchers from Zhejiang University in China, the Royal Institute of Technology in Sweden and National University of Singapore have decided to search for ways to reduce the cost and simplicity of invisibility devices.
The team of scientists relied on a computer optimization method, which relies on numerical methods and optimization algorithms to find the most suitable cloaking structure. Another useful method that was used was topology optimization — a method that is more useful for special cases of cloaking, where only a single direction of cloaking is required. These two methods resulted in an experimental demonstration in which scientists constructed a unidirectional cloak with a relative large invisible region made of a constant dielectric designed by topology optimization. The greatest advantage of their method is that, according to scientists, only 15 minutes were needed to fabricate the sample. Read full report here.
3. Diatoms Bring Quantum Effects to Life (September 13)
Physicists Michele Sclafani, Markus Arndt and colleagues from the University of Vienna have succeeded in finding a simple and cheap natural grating that could be used in diffraction experiments. In particular, they found that an exoskeleton of a marine alga could be used as a diffraction grating. For a full explanation watch the video above. Also, the full report is available here.