Light emission from emitters is a valuable piece of information in a variety of sensing and detection techniques, capable of labeling physical and biological processes which occur in the proximity of the emitter. Furthermore, quantum technologies are currently exploiting the statistics of single-emitters light emission aiming at turning particular emitters into fundamental units to sustain […]
“ The dose makes the poison!” This adage, attributed to Paracelsus, explains a basic principle of toxicology: a substance can produce a harmful effect only if it reaches a certain “toxic” concentration. [ 1 ] In reverse, it also means that a substance is not harmful below this toxic dose, and can even be vitally […]
In science we try to be very precise with the wording of our texts. One of the consequences of this is that we are not afraid of repeating some words in a paragraph, or even in a sentence, if that contributes to avoid possible misunderstandings, even though it may be not recommended stylistically. Another feature […]
The Nobel Prize in Chemistry 2016 was awarded to Jean-Pierre Sauvage, Fraser Stoddart and Ben Feringa “for the design and synthesis of molecular machines”. Molecular machines are made by one or a few molecules linked together, comprising several hundred atoms. If a molecule can use an energy input to perform a mechanical movement (output) it […]
Graphene is a diamagnetic material, this is, unable of becoming magnetic. However, a triangular piece of graphene is predicted to be magnetic. This apparent contradiction is a consequence of “magic” shapes in the structure of graphene flakes, which force electrons to “spin” more easily in one direction. Triangulene is a triangular graphene flake, which possesses […]
Condensed matter • Materials • Nanotechnology • Quantum physics • Theoretical physics
When two photons with the same energy interact with a nonlinear material, they “combine” and generate a new photon with twice the energy of the initial photons. More precisely, two photons at the fundamental frequency are absorbed by a plasmonic structure to emit one photon at the second-harmonic frequency. This is called second-harmonic generation. Second-harmonic […]
Graphene nanoribbons (GNRs), are strips of graphene with ultra-thin width (<50 nm). Graphene ribbons, introduced as a theoretical model by Mitsutaka Fujita and coauthors to examine the edge and nanoscale size effect in graphene, have emerged as a promising material for nanoelectronics, as they combine many of the extraordinary properties of graphene with a high […]
In the quantum theory of many-body systems, collective oscillations are called collective excitations. In a quantum context, everything is quantized. Hence, collective excitations become quantized modes because of the cooperative motion of the whole system as a result of interactions between particles. They may be electronic excitations in atoms and are referred excitons. In most […]
Superconductivity is a physical phenomenon in which some materials exhibit zero electrical resistance when cooled down below a certain critical temperature. As surprising as it can be, the critical temperature of these materials can be modified by reducing the sample size to about a million times the size of the objects we are used to […]
One of the greatest inventions of the 20th century, if not the greatest, was the transistor. It revolutionized the electronics industry and changed the way people around the world lived, learned, worked, and played. Its invention marked the beginning of solid state electronics which quickly reduced the size and power requirements of existing electronic tube […]