The band theory of metals has been subjected to experimental tests many times and is now the accepted model of the behaviour of conductors and insulators. But it has to be modified when it comes to superconductivity.
Electrical resistance is […]
In the early days of organic chemistry, the word aromatic was used to describe fragrant substances such as benzene (from coal distillate), benzaldehyde (from cherries, peaches, and almonds), and toluene (from tolu balsam).
It was soon realized, however, that substances […]
At a fundamental level the term “quantum computing” implies de use of quantum effects that have no classical analogue to process information. In a “classical computer” information is held in bits, which can have two alternative values (0 and 1). […]
In 1928, just two years after the formulation of quantum mechanics, the German physicist Arnold Sommerfeld modified the classical free-electron model by treating the electrons according to quantum mechanics. But the new theory still contained the unrealistic assumption that […]
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 […]
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 […]
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, […]
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. […]
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 “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.