Category archives: Theoretical physics

Plasmonic nanostructures confine light to dimensions far smaller than the free-space wavelength, as they mix optical fields with electronic excitations. It was not until the 1990s, with the appearance of accurate and reliable nanofabrication techniques, that plasmonics blossomed. It was found then that local fields around nanostructures could be directly measured by near-field scanning optical […]

The interactions between moving charges and magnetic fields can be quite complicated; more if we consider the quantum effects. One example is the collection of Hall effects. Imagine that we have a conductor or a semiconductor through which a current is flowing. Then we apply a strong transverse magnetic field. As a result, we can […]

Any physical law in which the magnitude of a physical quantity is proportional to the reciprocal of the square of the distance (1/r 2) from the source of that property is known as an inverse-square law. Newton’s law of gravitation and Coulomb’s law are both examples. When Newton proposed his law of gravitation in his […]

We started this series discussing the basic ingredients of the Universe: events, spacetime, causality. In the last chapter , we introduced massive objects (and thus, matter), which appear as a generalization of the so-called photon box. As it moves, any object traces a path. Physicists call it worldline . We established that a massive object […]

We all know what an insulator is, don’t we? An insulator is any substance that is a poor conductor of heat and electricity. Both properties ussually occur as a consequence of a lack of mobile electrons.If we want to dive a little deeper into the nature of insulators we make use of energy band theory […]

In the previous chapter of this series, we went over the subjective, relative separation of the network of events known as Spacetime into space and time. The speed of light played a major role in the discussion. In particular, we divided Spacetime into three regions (with respect to a particular event) defined by the existence […]

On 8 October 2013, following the discovery at CERN’s Large Hadron Collider of a new particle that appeared to be the long-sought Higgs boson predicted by the theory, it was announced that Peter Higgs and François Englert had been awarded the 2013 Nobel Prize in Physics. But they were the survivors of the bunch of […]

The concept of vector should be familiar: a quantity for which both magnitude and direction must be stated. This compares with a scalar quantity, where direction is not applicable, like temperature in a precise point. But, what if the magnitude varies with the direction? A vector would be a particular case, with only one direction […]

Black holes are vacuum solutions of the Einstein equation. Hence, the energy-momentum tensor for a black hole is null at every point of space. The only place where its mass can be located is where there is no space, i.e., at the singularity. Hence, for a Schwarzschild black hole, the mass is located at the […]

Controlling electron waves by harnessing phase-coherence and interference effects is a cornerstone for future nanoelectronics or quantum computing. To this end, design of platforms with well-defined, narrow, and low-loss propagation channels is essential. Nanoporous graphene (NPG) holds great potential for distributing and controlling currents on the nanoscale. But the effects derived from the wave nature […]