Category archives: Theoretical physics

Why Einstein must be wrong

Why Einstein must be wrong

PhysicsTheoretical physics

By Invited Researcher

Einstein Authors: Valerio Faraoni, Professor, Physics & Astronomy, Bishop’s University and Andrea Giusti, Postdoctoral fellow, Swiss Federal Institute of Technology Zurich Einstein’s theory of gravity — general relativity — has been very successful for more than a century. However, it has theoretical shortcomings. This is not surprising: the theory predicts its own failure at spacetime […]

The essential physics of the Mott metal-insulator transition at negligible computational cost

The essential physics of the Mott metal-insulator transition at negligible computational cost

DIPC Electronic PropertiesQuantum physicsTheoretical physics

By DIPC

Density functional theory (DFT) is a theoretical treatment of molecules in which the electron density is considered rather than the wave functions of individual electrons. In other words, it is a way of describing many-electron, in general, many-fermion, systems in which the energy is a funtional of the density of electrons (fermions). DFT is without […]

Magnetic fields and quantum symmetries, two old (and new) friends

Magnetic fields and quantum symmetries, two old (and new) friends

Quantum physicsTheoretical physics

By Instituto Carlos I

Symmetries play a fundamental role in Physics, and more specifically in Quantum Physics. It is well known that symmetries lead to degeneracy and to conserved currents in closed quantum systems (meaning that they do not interact with an environment). In the more realistic scenario of Open Quantum Systems (meaning that the quantum system does interact […]

Universal speed limits in thermodynamics away from equilibrium

Universal speed limits in thermodynamics away from equilibrium

DIPC Quantum SystemsPhysicsTheoretical physics

By DIPC

Many problems in science and engineering involve understanding how quickly a physical system transitions between distinguishable states and the energetic costs of advancing at a given speed. While theories such as thermodynamics and quantum mechanics put fundamental bounds on the dynamical evolution of physical systems, the form and function of the bounds differ. Rudolf Clausius’s […]

Second-harmonic generation in a quantum emitter – metallic nanoparticle hybrid

Second-harmonic generation in a quantum emitter – metallic nanoparticle hybrid

Condensed matterMaterialsNanotechnologyQuantum physicsTheoretical physics

By DIPC

When two photons with the same energy interact with a nonlinear material, they “combine” and generate a new photon with twice the energy of the initial photons. More precisely, two photons at the fundamental frequency are absorbed by a plasmonic structure to emit one photon at the second-harmonic frequency. This is called second-harmonic generation. Second-harmonic […]

An additional contribution to the spin Hall effect induced by an electric current

An additional contribution to the spin Hall effect induced by an electric current

Condensed matterMaterialsPhysicsTheoretical physics

By DIPC

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 […]

A local quantum emitter can be used to sense the environment of a molecule with the minimal quantum of energy

A local quantum emitter can be used to sense the environment of a molecule with the minimal quantum of energy

Condensed matterMaterialsNanotechnologyQuantum physicsTheoretical physics

By DIPC

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 […]

A theory of spin hall magnetoresistance to study magnetism at interfaces

A theory of spin hall magnetoresistance to study magnetism at interfaces

Condensed matterMaterialsQuantum physicsTheoretical physics

By DIPC

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 […]