Electrical energy is now the dominant form of energy consumption in industrialized countries and is an essential element in the operation of many of the devices we use every day. For decades, one of the most poorly understood yet most practical properties of a piece of solid matter was its ability, or lack of ability […]
One of the first recognized successes of the early quantum theory arose, not from the study of radiation, but from the theory of solids. Once again in the physics of the first half of the 20th century Albert Einstein was at the forefront; but this time the story is seldom told. After presenting the hypothesis […]
What more can be learnt from the chemistry of noble gases? Noble gases, the members of group 18 of the periodic table of elements (in previous terminology – group VIII) are known as monoatomic gases. The latter property is the result of their very low chemical reactivity thus, they do not form bonds between themselves […]
We finished our last article saying that it is one thing to accept this newly stated connection between electric and magnetic fields; but it is a little bit harder, and more interesting, to understand the physical necessity for such a connection. We will try to explain this necessity now avoiding the use of mathematics, step […]
We recently explored the concepts that Faraday introduced regarding the relationship between electricity and magnetism. In this article we focus on their treatment by Maxwell. The work of Oersted, Ampere, Henry, and finally Faraday had established two basic principles of electromagnetism: 1. An electric current in a conductor produces magnetic lines of force that circle […]
Newton suggested that the apparent colours of natural objects depend on which colour is most strongly reflected or scattered to the viewer by the object. In general, there is no simple way of predicting from the surface structure, chemical composition, etc., what colours a substance will reflect or scatter. However, the blue colour of the […]
We now refer to light as the form electromagnetic radiation to which the human eye is sensitive and on which our visual awareness of the universe and its contents relies. If we want to go a step forward we could say that its macroscopic behaviour is best explained by a set of differential equations proposed […]
We know that incident light can provoke a strong optical response in metallic nanostructures due to the excitation of resonant plasmonic modes, i.e, the electrons in the metal become excited by the photons in the incident light and oscillate collectively. One of the most interesting properties of plasmon resonances is their associated enhancement and confinement […]
In nature, light harvesting organisms make extensive use of energy and electron transfer between adjacent molecules. Thus, in the photosynthetic cell of an algae, bacterium, or plant, there are light-sensitive molecules called chromophores, which contain a π-conjugated system (a system with alternate single and double bonds), arranged in an antenna-shaped structure named a photocomplex. When […]
With “many-body problem” we usually make reference to one that is very difficult to obtain exact solutions for, because the system involves interactions between more than two bodies. This kind of problem appears both in classical and quantum systems. In order to understand the physics of many-body systems, it is necessary to make use of […]