Category archives: Theoretical physics

Beyond the point-dipole approximation

Beyond the point-dipole approximation

Condensed matterMaterialsQuantum physicsTheoretical physics

By DIPC

The wave nature of light expresses itself in the propagation all over space, showing an intrinsic limitation to be localized beyond the so-called diffraction limit which is of the order of half the wavelength of the photons propagating. However when interacting with matter, light often gets reflected, diffracted, scattered or absorbed depending on the interactions […]

How to extract the interacting spectral function from a ground state DFT calculation

How to extract the interacting spectral function from a ground state DFT calculation

Condensed matterNanotechnologyPhysicsQuantum physicsTheoretical physics

By DIPC

The electronic wave function of an n-electron molecule depends on 3n spatial and n spin coordinates. In a sense, the wave function of a many-electron molecule contains more information than is needed and is lacking in direct physical significance. This has prompted the search for methods that involve fewer variables than the wave function and […]

Higher-order topological insulators

Higher-order topological insulators

Condensed matterMaterialsPhysicsTheoretical physics

By DIPC

Topological insulators are materials with special universal properties, which are protected against perturbations. Such properties are theoretically described by topology, a branch of mathematics concerned with the properties of geometrical objects that are unchanged by continuous deformations. Concretely, topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have […]

Family unification (2): The SO(18) spinor strikes back

Family unification (2): The SO(18) spinor strikes back

Particle physicsPhysicsTheoretical physics

By Mario Reig

In the previous post, Family unification 1, we reviewed the historical development of Grand Unified Theories (GUT) of force and matter, i.e. Comprehensive Unification. We saw how the SO(18) spinor, 256, is able to accomodate the Standard Model (SM) family structure, however it contains too many families and, also, phenomenologically dangerous mirror families. During the […]

How dopants induce plasmon decay in graphene

How dopants induce plasmon decay in graphene

Condensed matterMaterialsNanotechnologyPhysicsTheoretical physics

By DIPC

For centuries, metals were employed in optical applications only as mirrors and gratings. New vistas opened up in the late 1970s and early 1980s with the discovery of surface-enhanced Raman scattering and the use of surface plasmon (collective electronic oscillations at the surface of metals) resonances for sensing. However, it was not until the 1990s […]

Metric structures in General Relativity

Metric structures in General Relativity

Theoretical physics

By Carlos Shahbazi

Reference contains the following statement: “Ashtekar’s formulation of general relativity taught us to think of gravitational theories as theories of connections, on a bare manifold with no metric structure. […] The idea that general relativity has its deepest formulation as a connection theory suggested immediately a new approach to the unification of general relativity with […]

The tautomerization of porphycene on Cu(111) in simple physical terms

The tautomerization of porphycene on Cu(111) in simple physical terms

Condensed matterQuantum physicsTheoretical physics

By DIPC

There are compounds, called isomers, that have the same molecular formulae but different molecular structures or different arrangements of atoms in space. In the so-called cis-trans isomerism, isomers have different positions of groups or specific atoms with respect to a double bond, a ring or a central atom. For example, the numbers in the name […]