Category Archives: Quantum physics
Helium atom scattering can measure electron−phonon interaction properties of surfaces
Atom scattering at low energies has a long history as a useful probe of surface properties. The most common atomic projectiles are helium atoms formed into a monoenergetic beam directed toward the surface with energies in the thermal range, meaning […]
Beyond the point-dipole approximation
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 […]
How to extract the interacting spectral function from a ground state DFT calculation
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 […]
Temperature dependence of rare earth valence has nothing to do with Kondo temperature
The scattering of conduction electrons in metals owing to impurities with magnetic moments is known as the Kondo effect, after Jun Kondo, who analysed the phenomenon in 1964. This scattering increases the electrical resistance and has the consequence that, in […]
What bounds a molecular solid together?
We usually think of crystals as composed of different atoms in certain proportions, this proportion being the molecular fórmula that represents the crystal. However, it is not surprising that any molecule could be the basis of a crystal structure, whether […]
Ordinary experience vs. quantum experience
We usually think of nature as existing completely independently of us and possessing a definite reality and behaviour even when we are not observing it. For instance, you assume that the world outside of the place where you are now […]
The Rise of Quantum Robots
Two of the hot topics in science an technology nowadays are related to Computer Science. They are Artificial Intelligence (AI) and Quantum Computing (QC). AI is a really old field, as humanity has dreamed of having autonomous machines for decades. […]
Our current image of atoms
The wave–particle dualism is a fundamental aspect of quantum mechanics. But, in order to explore this dualism properly and what it means for our image of atoms, it is necessary to review some ideas of probability.
In some situations, no […]
The size of atoms, uncertainty and relativity
You may have read somewhere that atoms are actually made up mostly of empty space. The usual description goes more or less as follows. At the centre of each atom there is a very tiny nucleus, which carries all of […]
Submolecular resolution using inelastic electron tunnelling spectroscopy at 5 K
What only a decades ago seemed impossible for chemists, determining the chemical structure of molecules directly from experimental images, is now routinely done. Not only that, the information about bond order, intermediates, and products of on-surface chemical reactions or charge […]