Category Physics

Between two mirrors, the quantum dot filters the light beams with just one photon per package out of the laser, so that only packages with multiple photons remain. Credit: Leiden Institute of Physics

Leiden physicists have manipulated light with large artificial atoms, ie quantum dots. Before, this has only been accomplished with actual atoms. It is an important step toward light-based quantum technology. When you point a laser pointer at the screen during a presentation, an immense number of light particles races through the air at a billion km/hour. They don’t travel in a continuous flow, but in packages containing varying numbers of particles. Sometimes as many as 4 so-called photons pass by, and other times none at all...

An illustration of the Migration Enhance Encapsulated Growth (MEEG) process to stabilize novel wide-bandgap two-dimensional nitride semiconductors that are not naturally occurring. MEEG is facilitated by defects in the graphene lattice that act as pathways for intercalation. When the gallium and nitrogen adatoms meet at the graphene/SiC interface, they chemically react to form two-dimensional gallium nitride. Credit: Z. Al Balushi and Stephen Weitzner, Penn State MatSE

A newly discovered method for making two-dimensional materials could lead to new and extraordinary properties, particularly in nitrides, say the Penn State materials scientists who discovered the process...

In the proposed experiment, two energy reservoirs (S and D) made of trapped ions transport energy quanta to each other by coupling to the spins in a quantum magnet placed between them. Credit: Alejandro Bermudez and Tobias Schaetz, New Journal of Physics. CC-BY-3.0

The first method to control transport of energy at the level of single energy quanta (which are mostly phonons) has been proposed. It’s theoretically possible to control the flow of single energy quanta through a quantum magnet using lasers with carefully controlled frequencies and intensities. If implemented, the method could allow researchers to explore quantum energy transport phenomena that are expected to be completely different than what is observed in macroscopic energy transport...

A short laser pulse travels through a diamond (black spheres) and excites electrons inside it. The strength of the excitation is measured using an attosecond ultraviolet pulse (violet). Credit: Matteo Lucchini, Copyright ETH Zurich

These insights are important for petahertz electronics of the future. Today’s electronic circuits already routinely work at frequencies of several gigahertz (a billion oscillations per second) up to terahertz (a thousand billion oscillations). Modern computers are as powerful as they are because tiny switches inside them steer electric currents in fractions of a billionth of a second...