Category archives: Theoretical physics

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 […]

A link between straintronics and valleytronics in graphene

A link between straintronics and valleytronics in graphene

Condensed matterMaterialsNanotechnologyQuantum physicsTheoretical physics

By DIPC

So-called “valleytronics” is a new type of electronics that could lead to faster and more efficient computer logic systems and data storage chips in next-generation devices. Valley electrons are so named because they carry a valley “degree of freedom.” This is a new way to harness electrons for information processing that’s in addition to utilizing […]

How to study magnetic Weyl fermions experimentally

How to study magnetic Weyl fermions experimentally

ChemistryCondensed matterQuantum physicsTheoretical physics

By DIPC

Imagine there exist a material in which an electron could be split into two quasiparticles. These two quasiparticles both would carry electric charge, move in opposite directions but could not move backwards. Furthermore these quasiparticles would be massless. And we can give them a fancy name, Weyl fermions. This seems to be at odds with […]

The geometry of String Compactifications (III): exploring the Calabi-Yau manifold

The geometry of String Compactifications (III): exploring the Calabi-Yau manifold

PhysicsTheoretical physics

By Carlos Shahbazi

In the previous articles (I, II), we have characterized the simplest class of supersymmetric heterotic compactification backgrounds. In particular, we have finished the second article with the following result: There is a class of admissible Heterotic internal manifolds characterized as being six-dimensional, oriented, spin, Riemannian compact manifolds admitting a parallel spinor respect to the Levi-Civita […]

The geometry of String Theory compactifications (II): finding the Calabi-Yau manifold

The geometry of String Theory compactifications (II): finding the Calabi-Yau manifold

PhysicsTheoretical physics

By Carlos Shahbazi

This is the second of the series of articles on the geometry of String Theory compactifications. Before reading this note, the interested reader may want to read the first note, where the concept of compactification background is introduced in the context of String Theory and M-Theory compactifications. As it is well known, to be well-defined […]