Holometer experiment to test if the universe is a hologram

Many ideas in theoretical physics involve extra dimensions, but the possibility that the universe has only two dimensions could also have surprising implications. The idea is that space on the ultra-small Planck scale is two-dimensional, and the third dimension is inextricably linked with time. If this is the case, then our three-dimensional universe is nothing more than a hologram of a two-dimensional universe.

Topological insulators could help define fundamental constants

A newly discovered class of materials known as "topological insulators" could help physicists to obtain new ways of defining the three basic physical constants – the speed of light (c); the charge of the proton (e); and Planck’s constant (h). That’s the claim of a team of physicists in the US, which has proposed a new experiment to measure the fine-structure constant (α), which is a function of h, c and e, by scattering light from such a material. Topological insulators are unusual in that electrical current flows well on their surface, but not through their bulk.

The quest for dilute ferromagnetism in semiconductors: Guides and misguides by theory

A material that exhibits both ferromagnetic and semiconductor properties offers the exciting prospect of combining nonvolatile magnetic storage and conventional semiconductor electronics in a single device. Magnetic semiconductors offer a number of interesting possibilities in the pursuit of  spintronics , a branch of science and technology that exploits the spin dimension of the electron in addition to its charge, for novel electronic devices. These materials combine the properties of a semiconductor and a magnetic material, providing, for instance, a way to create 100 % spin-polarized currents, and by the same token, the promise of electrical control of magnetic effects. While in some magnetic semiconductors, for example, magnetite, all of the material’s constituent ions are intrinsically magnetic (  concentrated magnets  ), the most recent focus has been on nonmagnetic semiconductor host materials that can be doped by a small amount of magnetic transition-metal ions or by defects that promote magnetism (  dilute magnets  ).